Projection exposure apparatus and method, catadioptric optical system and manufacturing method of devices

ABSTRACT

A projection exposure apparatus includes a projection optical system, which is arranged in an optical path between a first surface and a second surface, projects a pattern on a negative plate arranged on the first surface onto a workpiece arranged on the second surface and exposes the pattern thereon. The projection optical system includes a first imaging optical subsystem having a dioptric imaging optical system; a second imaging optical subsystem having a concave reflecting system; a third imaging optical subsystem having a dioptric imaging optical system; a first folding mirror arranged in an optical path between the first imaging optical subsystem and the second imaging optical subsystem; and a second folding mirror arranged in an optical path between the second imaging optical subsystem and the third imaging optical subsystem. The first imaging optical subsystem forms a first intermediate image and the second imaging optical subsystem forms a second intermediate image.

TECHNICAL FIELD

The present invention relates to a projection exposure apparatus andmethod used in transferring a negative plate (mask, reticle and thelike) onto a workpiece (substrate and the like) in a photolithographicprocess for manufacturing devices, such as semiconductor devices, imagepickup devices, liquid crystal display devices or thin-film magneticheads and so on and relates to a high-resolution catadioptric typeprojection optical system suitable for such projection exposureapparatus.

BACKGROUND ART

In the photolithographic process for manufacturing semiconductor devicesand so on, projection exposure apparatus in which a pattern image of aphotomask or a reticle (generically called “reticle” hereafter) isexposed onto a workpiece such as a wafer, or a glass plate and the likecoated with a photoresist and the like via projection optical systemhave been used. Then, the resolving power (resolution) required for theprojection optical system of the projection exposure apparatus has beenincreased more and more in order to improve the integration level ofsemiconductor devices and so on. As a result, the wavelength ofilluminating light (exposure light) must be shortened and the numericalaperture (NA) of the projection optical system must be increased.

For example, if an exposure light with wavelength of 180 nm or less isused, it is possible to achieve a high resolution of 0.1 μm or less.However, if the wavelength of illuminating light is shortened, theabsorption of light becomes remarkable, and the kinds of glass materials(optical materials) that can be practically used are limited. Inparticular, if the wavelength of illuminating light becomes 180 nm orless, the practically usable glass material is limited to fluorite only.As a result, the correction of chromatic aberrations becomes impossiblein a dioptric type projection optical system. Here, the dioptric typeoptical system is an optical system which does not contain reflectivesurfaces (concave reflective mirrors and convex reflective mirrors) withpower, but only contains transmissive optical members, such as lenscomponents.

As described above, there is a limit to the allowable chromaticaberrations in a dioptric type projection optical system, and a verynarrow band of laser light source is needed. In this case, an increasein the cost of laser light source and a decrease of its output areunavoidable. Moreover, many positive lenses and negative lenses must bearranged in a dioptric optical system to bring the Petzval sum, whichaffects the curvature of image field, close to 0. By contrast, a concavereflective mirror corresponds to a positive lens as an optical elementfor converging light, but it is different from a positive lens in thatno chromatic aberrations occur and that the Petzval sum takes a negativevalue (a positive lens takes a positive value in this connection).

In a so called catadioptric optical system constituted by combining aconcave reflective mirror and lenses, the above characteristic of theconcave reflective mirror is best used to the maximum in an opticaldesign and good correction of aberrations beginning with the chromaticaberrations and the curvature of image field are possible in spite ofits simple construction. However, the manner in which an incident beamand an emergent beam are separated for a concave reflective mirror ispoint of greatest difficulty, and various techniques for this separationhave been proposed.

For example, Japanese Laid-Open Application No. 8-62502 (U.S. Pat. No.5,861,997) discloses a catadioptric optical system which is acatadioptric optical system using an exposure region (off-axis visualfield) free of an optical axis in a projection exposure apparatus and isof a type wherein intermediate images are formed twice on the way of theoptical system and the separation of beam is spatially conducted in thevicinity of the intermediate images.

SUMMARY OF THE INVENTION

The present invention is aimed at providing a catadioptric opticalsystem which facilitates optical adjustment and mechanical design, fullycorrects aberrations beginning with chromatic aberrations and achieves ahigh resolution of 0.1 μm or less using a light with wavelength of 180μnm or less in the vacuum ultraviolet wavelength region.

Moreover, the present invention is aimed at providing a projectionexposure apparatus and an exposure method which results in facilitatingoptical adjustment and mechanical design, fully corrects aberrationsbeginning with chromatic aberrations, and ensures a high resolution of,e.g., 0.1 μm or less and lowly sets up the off-axis quantity of aneffective exposure region from the optical axis.

Furthermore, the present invention is aimed at providing a manufacturingmethod of microdevices which results in the manufacture of goodmicro-devices at a high resolution of, e.g., 0.1 μm or less.

To achieve the previous objects, a catadioptric optical system accordingto a first aspect of the preferred embodiment is a catadioptric opticalsystem for forming a reduced image of a first surface onto a secondsurface and comprises a first imaging optical subsystem for forming afirst intermediate image of the first surface, which is arranged onto anoptical path between the first surface and the second surface and has adioptric imaging optical system; a first folding mirror for deflecting abeam incident to the first intermediate image or a beam from the firstintermediate image, which is arranged in the vicinity of a position forforming the first intermediate image; a second imaging optical subsystemfor forming a second intermediate image of a magnification factor nearlyequal to the first intermediate image in the vicinity of a position forforming the first intermediate image based on the beam from the firstintermediate image, which has a concave reflecting mirror and at leastone negative lens; a second folding mirror for deflecting a beamincident to the second intermediate image or a beam from the secondintermediate image, which is arranged in the vicinity of a position forforming the second intermediate image; and a third imaging opticalsubsystem for forming the reduced image onto the second surface based ona beam from the second intermediate image, which is arranged onto anoptical path between the second imaging optical subsystem and the secondsurface and has a dioptric imaging optical system.

To achieve the objects, the catadioptric optical system according to asecond aspect of the preferred embodiment is a catadioptric opticalsystem for forming a reduced image of a first surface onto a secondsurface and comprises a first imaging optical subsystem, arranged in anoptical path between the first surface and the second surface, having afirst optical axis, and a dioptric imaging optical system; a secondimaging optical subsystem, arranged in an optical path between the firstimaging optical system and the second surface, having a concavereflecting mirror and a second optical axis; and a third imaging opticalsubsystem, arranged in an optical path between the second iamgingoptical system and the second surface, having a third optical axis and adioptric imaging optical system where the first optical axis and thesecond optical axis intersect with each other, and the second opticalaxis and the third optical axis intersect with each other.

To achieve the objects, a catadioptric optical system according to athird aspect of the preferred embodiment is a catadioptric opticalsystem for forming a reduced image of a first surface onto a secondsurface and comprises a first imaging optical subsystem, arranged in anoptical path between the first surface and the second surface, having afirst optical axis, and a dioptric imaging optical system; a secondimaging optical subsystem, arranged in an optical path between the firstimaging optical subsystem and the second surface, having a concavereflecting mirror and a second optical axis; and a third imaging opticalsubsystem, arranged in an optical path between the second imagingoptical subsystem and the second surface, having a third optical axis,and a dioptric imaging optical system; where the first optical axis andthe third optical axis are located on a common axis.

To achieve the previous objects, a projection exposure apparatusaccording to a fourth aspect of the preferred embodiment comprises: aprojection optical system in which a pattern on a negative platearranged in the first surface is projected onto a workpiece arranged inthe second surface and exposed, which is arranged in an optical pathbetween the first surface and the second surface and the projectionoptical system comprises a first imaging optical subsystem which has adioptric imaging optical system; a second imaging optical subsystemwhich has a concave reflecting mirror; a third imaging optical subsystemwhich has a dioptric imaging optical system; a first folding mirrorwhich is arranged in an optical path between the first imaging opticalsubsystem and the second imaging optical subsystem; a second foldingmirror which is arranged in an optical path between the second imagingoptical subsystem and the third imaging optical subsystem; where thefirst imaging optical subsystem forms a first intermediate image on anoptical path between the first imaging optical subsystem and the secondimaging optical subsystem and the second imaging optical subsystem formsa second intermediate image on an optical path between the secondimaging optical subsystem and the third imaging optical subsystem.

To achieve the previous mentioned objects, an exposure method accordingto a fifth aspect of the preferred embodiment is an exposure method inwhich a pattern on a negative plate is projected onto a workpiece via aprojection optical system and exposed and comprises the following steps:an illuminating light of ultraviolet region is led to the pattern on thenegative plate; the illuminating light is led to the first imagingoptical subsystem having a dioptric imaging optical system via thepattern to form a first intermediate image of the pattern on theprojection negative plate; a light from the first intermediate image isled to a second imaging optical subsystem having a concave reflectingmirror to form a second intermediate image; a light from the secondintermediate image is led to a third imaging optical subsystem having adioptric imaging optical system to form a final image on the workpiece;a light from the first imaging optical subsystem is deflected by a firstfolding mirror arranged on an optical path between the firstintermediate image and the second imaging optical subsystem; and a lightfrom the second imaging optical subsystem is deflected by a secondfolding mirror arranged on an optical path between the secondintermediate image and the third imaging optical subsystem.

To achieve the previous mentioned objects, an imaging optical systemaccording to a sixth aspect of the preferred embodiment is an imagingoptical system for forming an image of a first surface onto a secondsurface and comprises at least one reflecting surface arranged betweenthe first surface and the second surface, and the reflecting surfacecomprises a metallic reflecting film and a correction film arranged onthe metallic reflecting film for correcting a phase difference which iscaused by a difference in polarized state possessed by a reflected lightfrom the metallic reflecting film.

To achieve the previous objects, a projection exposure apparatusaccording to a seventh aspect of the preferred embodiment is aprojection exposure apparatus in which a pattern on a negative platearranged on a first surface is projected onto a workpiece arranged onthe second surface and exposed and comprises that the projection opticalsystem arranged in an optical path between the first surface and thesecond surface and having at least one reflecting members and thereflecting member reflect a light so that a phase difference of a Ppolarized component and a S polarized component substantially does notexist when the P polarized component and the S polarized component cometo the photosensitive substrate.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating the basic construction of acatadioptric optical system of the present invention.

FIG. 2 is a diagram schematically illustrating the general constructionof a projection exposure apparatus provided with catadioptric opticalsystems according to embodiments of the present invention as aprojection optical system.

FIG. 3 is a diagram illustrating the positional relation between arectangular exposure region (i.e., effective exposure region) formed ona wafer W and a reference optical axis.

FIG. 4 is a diagram illustrating the lens construction of a catadioptricoptical system (projection optical system PL) according to a firstembodiment.

FIG. 5 is a diagram illustrating the lateral aberrations in the firstembodiment.

FIG. 6 is a diagram for illustrating the lens construction of acatadioptric optical system (projection optical system PL) according toa second embodiment.

FIG. 7 is a diagram illustrating the lateral aberrations in the secondembodiment.

FIG. 8 is a diagram illustrating the general construction of theprojection exposure apparatus of the embodiment shown in FIG. 2.

FIG. 9 is an enlarged view illustrating a part related to anilluminating optical system which constitutes a part of the projectionexposure apparatus of FIG. 8.

FIG. 10 is an enlarged view illustrating a part related to anilluminating optical system which constitutes a part of the projectionexposure apparatus of FIG. 8.

FIG. 11 is a diagram illustrating a flowchart of a manufacturing exampleof devices (semiconductor chip such as IC or LSI and the like, liquidcrystal panel, CCD, thin-film magnetic head, micro-machine and so on).

FIG. 12 is a drawing for illustrating one example of detailed flow ofstep 204 of FIG. 11 in the case of a semiconductor device.

FIG. 13A is a diagram illustrating the lens construction of acatadioptric optical system (projection optical system PL) according toa third embodiment.

FIG. 13B is a diagram for illustrating principal parts of a catadioptricoptical system (projection optical system PL) according to a thirdembodiment.

FIG. 14 is a diagram illustrating the lateral aberrations in the thirdembodiment.

FIG. 15 is a diagram illustrating the construction of modificationexample 1 of the third embodiment.

FIG. 16 is a diagram illustrating the construction of modificationexample 2 of the third embodiment.

FIG. 17 is a diagram illustrating the construction of modificationexample 3 of the third embodiment.

FIG. 18 is a diagram illustrating the construction of modificationexample 4 of the third embodiment.

FIG. 19 is a drawing illustrating the construction of modificationexample 5 of the third embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 is a diagram illustrating the basic construction of acatadioptric optical system of the present invention. In the diagram,the catadioptric optical system of the present invention is applied tothe projection optical system of a projection exposure apparatus.

As shown in FIG. 1, the catadioptric optical system of the presentinvention is provided with a dioptric type first imaging optical systemG1 for forming a first intermediate image of a pattern of reticle Rarranged as a first surface as a negative plate.

A first optical path folding mirror 1 is arranged in the vicinity offormation position of the first intermediate image formed by the firstimaging optical system G1. The first optical path folding mirror 1deflects a beam incident to the first intermediate image or a beam fromthe first intermediate image to a second imaging optical system G2. Thesecond imaging optical system G2 has a concave reflecting mirror (CM)and at least one negative lens 3, and a second intermediate image (animage of the first intermediate image and a secondary image of thepattern) nearly equal in size to the first intermediate image is formedin the vicinity of formation position of the first intermediate imagebased on the beam from the first intermediate image.

A second optical path folding mirror 2 is arranged in the vicinity offormation position of the second intermediate image formed by the secondimaging optical system G2. The second optical path folding mirror 2deflects a beam incident to the second intermediate image or a beam fromthe second intermediate image to a dioptric type third imaging opticalsystem G3. Here, the reflecting surface of the first optical pathfolding mirror 1 and the reflecting surface of the second optical pathfolding mirror 2 are positioned so as not to overlap spatially. Thethird imaging optical system G3 forms a reduced image of pattern of thereticle (an image of the second intermediate image and a final image ofthe catadioptric optical system) on a wafer W arranged as a secondsurface as photosensitive substrate based on the beam from the secondintermediate image.

In the above construction, a chromatic aberration and a positive Petzvalsum produced by the first imaging optical system G1 and the thirdimaging optical system G3, which are dioptric optical systems comprisingplural lenses, are compensated by the concave reflecting mirror CM andthe negative lens(es) 3. Moreover, the second intermediate image can beformed in the vicinity of the first intermediate image by a constructionthat the second imaging optical system G2 has a nearly equal (unit)magnification. In the present invention, the distance from the opticalaxis of an exposure region (i.e., an effective exposure region), namely,the off-axis quantity can be lowly set up by conducting an optical pathseparation in the vicinity of these two intermediate images. This is notonly favorable in aberration correction, but also favorable inminiaturization of optical systems, optical adjustment, mechanicaldesign, manufacturing cost, and so on.

As described above, the second imaging optical system G2 bears thecompensation of the chromatic aberration and the positive Petzval sumproduced by the first imaging optical system G1 and the third imagingoptical system G3 all alone. For this reason, a large power (dioptricpower) must be set up for both the concave reflecting mirror CM and thenegative lens(es) 3 constituting the second imaging optical system G2.Therefore, if the symmetry of the second imaging optical system G2collapses, the occurrence of asymmetrical chromatic aberrations such aslateral chromatic aberration or chromatic coma aberration increases,thus an enough resolution power cannot be obtained. Accordingly, thepresent invention succeeds in ensuring good symmetry and preventing theprevious mentioned asymmetrical chromatic aberrations by adopting aconstruction which results in a set up having a nearly unitymagnification for the second imaging optical system G2 and by arrangingthe concave reflecting mirror CM in the vicinity of its pupil position.

The construction of the present invention is described in more detailhereafter with reference to the following conditions.

In the present invention, it is preferable that the magnification β2satisfies the following condition (1).0.82<|β2|<1.20  (1)

Condition (1) specifies an appropriate range of magnification β2 of thesecond imaging optical system G2.

If this condition (1) is not satisfied, it is not preferred because theoff-axis quantity for the optical path separation increases, thus thelarge scale and complication of the optical systems cannot be avoided.In addition, it is not preferred because the occurrence of asymmetricalchromatic aberrations such as lateral chromatic aberration or chromaticcoma aberration and the like cannot be prevented.

It is more preferable that the lower limit is 0.85 and the upper limitis 1.15 for condition (1). It is even more preferable that the lowerlimit is 0.87 for condition (1).

In the present invention, it is preferable that the following condition(2) is satisfied.|L 1−L 2|/|L 1|<0.15  (2)

Here, L1 is the distance between the first intermediate image and theconcave reflecting mirror CM in the second imaging optical system G2along the optical axis. L2 is the distance between the secondintermediate image and the concave reflecting mirror CM in the secondimaging optical system G2 along the optical axis. In the case of thepresent invention, L1 and L2 are distances from the intersection of theoptical axis and a perpendicular from the intermediate image to theoptical axis when extending the perpendicular down to the concavereflecting mirror CM along the optical axis because the intermediateimage is not formed on the optical axis.

Condition (2) specifies a positional relation between the firstintermediate image formed by the first imaging optical system G1 and thesecond intermediate image formed by the second imaging optical systemG2.

If condition (1) is not satisfied, it is not preferred because theoff-axis quantity for the optical path separation increases, thus thelarge scale and complication of the optical systems cannot be avoided.

It is more preferable that the upper limit is 0.85 for condition (2).

In the present invention, it is preferable that the first intermediateimage is formed on the optical path between the first optical pathfolding mirror 1 and the second imaging optical system G2, and thesecond intermediate image is formed on the optical path between thesecond imaging optical system G2 and the second optical path foldingmirror 2. In this case, the stability of the optical systems increasesand the optical adjustment and mechanical design become easy because thedistance between first surface and second surface can be shortened.Moreover, when the present invention is applied to a projection exposureapparatus, the height of the whole apparatus can be reduced because thedistance between the reticle R arranged on the first surface and thewafer arranged on second surface is shortened.

In the present invention, it is preferable that the following condition(3) is satisfied.0.20<|β|/|β1|<0.50  (3)

Here, β is the magnification of the catadioptric optical system(projection optical system if applied to a projection exposureapparatus). β1 is the magnification of the first imaging optical systemG1.

Condition (3) specifies an appropriate range of the ratio of themagnification of the whole system β to the magnification of the firstimaging optical system G1.

If the ratio is more than the upper limit of condition (3), it isundesirable because the angle of dispersion (angle range) of a beamincident into the first optical path folding mirror 1 and the secondoptical path folding mirror 2 increases and consequently the design of areflecting film becomes difficult. In particular, reflecting filmmaterials usable for a light with wavelength shorter than 180 nm arealso limited, thus it is difficult to keep the reflectivity at a highlevel in a broad angular band constant. The difference in reflectivitybetween P polarized light and S polarized light or the phase change alsochanges with the angle of incidence and therefore in its turn isassociated with deterioration of the imaging property of the wholesystem.

On the other hand, if the ratio is less than the lower limit of thiscondition (3), it is undesirable because the load of magnificationfactor, which should be the burden of the third imaging optical systemG3, rises, and thus a large scale of the optical systems cannot beavoided.

Moreover, it is more preferable that the lower limit of condition (3) is0.25 and its upper limit is 0.46.

Furthermore, in the present invention, it is preferable that thecatadioptric optical system is a telecentric optical system on bothsides of the first surface and the second surface. When the system isapplied to a projection exposure apparatus, it is preferable that theprojection optical system is a telecentric optical system on bothreticle side and wafer side. This construction enables to lowly suppressthe magnification error or distortion of image when positional errors orwarp of the reticle or wafer and the like occur. Furthermore, it ispreferable that an angle made by a light passing through the center ofbeam (i.e., principal ray) becomes 50 minutes or less in the whole fieldso that the optical systems are substantially telecentric.

In the present invention, it is preferable to satisfy the followingcondition (4), in addition to the catadioptric optical system, which istelecentric on both sides.|E−D|/|E|<0.24  (4)

Here, E is the distance between the surface on the image side of thefirst imaging optical system G1 and its exit pupil position along theoptical axis. D is the distance by air conversion from the surface onthe image side of the first imaging optical system G1 to the concavereflecting mirror CM in the second imaging optical system G2 along theoptical axis.

Condition (4) specifies a positional relation between the exit pupil ofthe first imaging optical system G1 and the concave reflecting mirrorCM.

If condition (4) is not satisfied, it is not preferable because theoccurrence of asymmetrical chromatic aberrations such as lateralchromatic aberration or chromatic coma aberration and the like cannot belowly suppressed.

Moreover, it is more preferable that the upper limit of condition (4) is0.17.

Furthermore, it is preferable in the present invention that theintersection line of an assumed extension plane of the reflecting plane(an assumed plane obtained by infinitely extending a planar reflectingplane) of the first optical path folding mirror 1 and an assumedextension plane of the reflecting plane of the second optical pathfolding mirror 2 is so set up that an optical axis AX1 of the firstimaging optical system G1, an optical axis AX2 of the second imagingoptical system G2 and an optical axis AX3 of the third imaging opticalsystem G3 intersect at one point (reference point). This constructionresults in the optical axis AX1 of the first imaging optical system G1and the optical axis AX3 of the third imaging optical system G3 becominga common optical axis, and particularly enables to position the threeoptical axes AX1–AX3 and the two reflecting planes in relation to onereference point. Therefore, the stability of the optical systemsincreases, and the optical adjustment and mechanical design become easy.An even higher accuracy optical adjustment can be facilitated and evenhigher stability can be achieved by setting the optical systems so thatthe optical axis AX2 is perpendicular to the optical axis AX1 of thefirst imaging optical system G1 and the optical axis AX3 of the thirdimaging optical system G3.

Furthermore, it is preferable in the present invention that all lensesconstituting the first imaging optical system G1 and all lensesconstituting the third imaging optical system G3 are arranged along asingle optical axis. This construction causes any flexure due to gravityto become rotationally symmetrical and provides to lowly suppress thedeterioration of imaging property due to the optical adjustment. Inparticular, when it is applied to a projection exposure apparatus, thereticle R and the wafer W can be arranged parallel to each other along aplane perpendicular to the gravity direction (i.e., horizontal plane)and all lenses constituting the first imaging optical system G1 and thethird imaging optical system G3 can be arranged horizontally along asingle optical axis in the gravity direction by using the first imagingoptical system G1 and the third imaging optical system G3 in an uprightposition along the common optical axis. As a result, the reticle, waferand most of the lenses constituting the projection optical system areheld horizontally, not subjected to an asymmetrical deformation due totheir own weight, and this is very favorable in ensuring opticaladjustment, mechanical design, high resolution and the like.

Further, it is preferable in the present invention that over 85% of thenumber of lenses in all lenses constituting the catadioptric opticalsystem (the projection optical system in the case of applying it to aprojection exposure apparatus) are arranged along a single optical axis.For example, if the first imaging optical system G1 and the thirdimaging optical system G3 are used in an upright position along thecommon optical axis, almost all lenses in many lenses constituting theoptical systems are held horizontally and an asymmetrical deformationdue to their own weight does not occur by this construction, thereforeit is further favorable in ensuring optical adjustment, mechanicaldesign, high resolution and the like.

Additionally, as described above, the negative lens(es) 3 in the secondimaging optical system G2 requires a large power (refractive power) tocompensate for chromatic aberrations being produced by the first imagingoptical system G1 and the third imaging optical system G3 alone.Accordingly, it is preferable in the present invention that the secondimaging optical system G2 has at least two negative lenses 3. Thisconstruction enables to divide and bear a necessary power with at leasttwo negative lenses and in its turn provides to constitute stabilizedoptical systems.

Embodiments of the present invention are described hereafter, withreference to the following drawings.

FIG. 2 is a diagram schematically showing the general construction of aprojection exposure apparatus which is provided with a catadioptricoptical system according to embodiments of the present invention as aprojection optical system. In FIG. 2, the Z axis is set up in parallelto a reference optical axis AX of the catadioptric optical systemconstituting a projection optical system PL, the Y axis is set up inparallel to the paper surface of FIG. 2 in a plane perpendicular to theoptical axis AX. Moreover, FIG. 2 schematically shows the generalconstruction of a projection exposure apparatus, and its detailedconstruction will be described later in FIGS. 8–10.

The described projection exposure apparatus is provided with, e.g., a F₂laser (wavelength 157.624 nm) as a light source 100 for supplying anilluminating light of ultraviolet region. The illuminating lightemergent from the light source 100 evenly illuminates a reticle R wherea given pattern is formed.

Moreover, an optical path between the light source 100 and anilluminating optical system IL is sealed by a casing (not shown), and aspace from the light source 100 to an optical member on the reticle sidein the illuminating optical system IL is filled with an inert gas, suchas helium gas or nitrogen gas and the like being a gas with a lowabsorptivity of exposure light, or kept in a nearly vacuum state.

The reticle R is in parallel held in the XY plane on a reticle stage RSvia a reticle holder RH. A pattern to be transferred is formed on thereticle, and a rectangular (slit-like) pattern region with a long sidealong the X direction and a short side along the Y direction in thewhole pattern region is illuminated. The reticle stage RS is movabletwo-dimensionally along the reticle surface (i.e., the XY plane) by theaction of a driving system whose illustration is omitted and is soconstituted that its position coordinates are measured and positionallycontrolled by an interferometer RIF using a reticle moving (measuring)mirror RM.

A light from the pattern formed on the reticle forms a reticle patternimage on a wafer W, which is a photosensitive substrate, via acatadioptric type projection optical system PL. The wafer W is inparallel held on the XY plane on a wafer stage WS via a wafer table(wafer holder) WT. Then, a pattern image is formed in a rectangularexposure region with a long side along the X direction and a short sidealong the Y direction on the wafer W so as to correspond to therectangular illuminating region on the reticle R optically. The waferstage WS is movable two-dimensionally along the wafer surface (i.e., theXY plane) by the action of a driving system whose illustration isomitted, and its position coordinates are measured and positionallycontrolled by an interferometer WIF using a wafer moving (measuring)mirror WM.

FIG. 3 is a diagram showing a positional relation between therectangular exposure region (i.e., effective exposure region) formed onthe wafer W and the reference optical axis.

As shown in FIG. 3, in the embodiments, a rectangular effective exposureregion ER having a desirable size is set up in a position separated fromthe reference axis AX by only an off-axis quantity A in the +Y directionin a circular region (image circle) with a radius B and with thereference axis AX as its center. Here, the X-direction length of theeffective exposure region ER is LX and its Y-direction length is LY.

In other words, in the embodiments, the rectangular effective exposureregion ER having a desirable size is set up in a position separated fromthe reference axis AX by an off-axis quantity A in the +Y direction, andthe radius B of the circular image circle IF is specified so as toinclude the effective exposure region ER with the reference axis AX asits center.

Therefore, a description is omitted, but a rectangular illuminationregion (i.e., effective illumination region) with a size and a shapecorresponding to the effective exposure region ER is formed in aposition separated from the reference axis AX by only a distancecorresponding to the off-axis quantity A in the −Y direction.

Moreover, in the described projection exposure apparatus, the projectionoptical system PL is so constituted that its inside is kept in an air(gas)-tight state between an optical member arranged on the reticle side(lens L11 in the embodiments) and an optical member arranged on thewafer side (lens L311 in the embodiments) among optical membersconstituting the projection optical system PL, and is filled with aninert gas such as helium gas or nitrogen gas and the like or kept in anearly vacuum state.

Furthermore, the reticle R and the reticle stage RS and the like arearranged in a narrow optical path between the illumination opticalsystem IL and the projection optical system PL, but an inert gas, suchas nitrogen or helium gas and the like, is filled into a casing (notshown) which seals and encloses the reticle R and the reticle stage RSand the like or the casing is kept in a nearly vacuum state.

Additionally, the wafer W and the wafer stage WS and the like arearranged in a narrow optical path between the projection optical systemPL and the wafer W, but an inert gas, such as nitrogen or helium gas andthe like, is filled into a casing (not shown) which seals and enclosesthe wafer W and the wafer stage WS and the like or the casing is kept ina nearly vacuum state.

Thus, an atmosphere in which the exposure light is almost not absorbedis formed over the whole optical path from the light source 100 to thewafer W.

As described above, the illumination region on the reticle and theexposure region on the wafer W (i.e., effective exposure region ER)specified by the projection optical system PL are rectangles with shortsides in the Y direction. Therefore, the reticle pattern is scanned andexposed for a region which has a width equal to the long side of theexposure region on the wafer W and has a length corresponding to thescan quantity (moving quantity) of the wafer W by moving (scanning) thereticle stage RS and the wafer stage WS and in its turn the reticle Rand the wafer W synchronously in the same direction (i.e., sameorientation) along the short-side direction, i.e., the Y direction ofthe rectangular exposure region and the illumination region, while thepositional control of the reticle R and the wafer W is taken by adriving system or an interferometer (RIF, WIF) and the like.

In the embodiments, the projection optical system PL including thecatadioptric optical system is provided with a dioptric type firstimaging optical system G1 for forming a first intermediate image of thepattern of the reticle arranged on the first surface, a second imagingoptical system G2 comprising a concave reflecting mirror CM and twonegative lenses 3 for forming a second intermediate image nearly unitaryto the first intermediate image (a nearly equal size image of the firstintermediate image and a secondary image of the reticle pattern) and adioptric type third imaging optical system G3 for forming a final imageof the reticle pattern (a reduced image of the reticle pattern) on thewafer W arranged on the second surface based on a light from the secondintermediate image.

Moreover, in the embodiments, a first optical path folding mirror 1 fordeflecting the light from the first imaging optical system G1 to thesecond imaging optical system G2 is arranged in the vicinity of theformation position of the first intermediate image in an optical pathbetween the first imaging optical system G1 and the second imagingoptical system G2. A second optical path folding mirror 2 for deflectingthe light from the second imaging optical system G2 to the third imagingoptical system G3 is arranged in the vicinity of the formation positionof the second intermediate image in an optical path between the secondimaging optical system G2 and the second imaging optical system G3. Inthe embodiments, the first intermediate image and the secondintermediate image are formed in an optical path between the firstoptical path folding mirror 1 and the second imaging optical system G2and an optical path between the second imaging optical system G2 and thesecond optical path folding mirror 2, respectively.

Furthermore, in the embodiments, the first imaging optical system G1 hasa linearly extended optical axis AX1, the third imaging optical systemG3 has a linearly extended optical axis AX3, the optical axis AX1 andthe optical axis AX3 are set up so as to coincide with the referenceoptical axis AX, which is a common single axis. As a result, the reticleand the wafer W are arranged in parallel to each other along a planeperpendicular to the gravity direction, i.e., a horizontal plane. Inaddition, all lenses constituting the first imaging optical system G1and all lenses constituting the third imaging optical system G3 are alsoarranged along the horizontal plane on the reference optical axis AX.

On the other hand, the second imaging optical system G2 also has alinearly extended optical axis AX2, and this optical axis AX2 is set upso as to be perpendicular to the reference optical axis AX, which is thecommon single axis. Moreover, both the first optical path folding mirror1 and the second optical path folding mirror 2 have planar reflectingsurfaces and are integrally constituted as one optical member (oneoptical path folding mirror FM) with two reflecting planes. Theintersection line of these two reflecting planes (strictly theintersection line of their assumed extended planes) are set up so thatthe axis AX1 of the first imaging optical system G1, the axis AX2 of thesecond imaging optical system G2 and the axis AX3 of the third imagingoptical system G3 intersect at one point. Furthermore, both the firstoptical path folding mirror 1 and the second optical path folding mirror2 are constituted as front surface reflecting mirrors in the firstembodiment and in the second embodiment, and both the first optical pathfolding mirror 1 and the second optical path folding mirror 2 areconstituted as rear (back) surface reflecting mirrors in the thirdembodiment. The smaller the interval between the effective region ofreflecting plane of the optical path folding mirror FM and optical AX isset up, the less the off-axis quantity A of the effective exposureregion will be.

In the embodiments, fluorite (CaF₂ crystal) is used for all dioptricoptical members (lens component) constituting the projection opticalsystem. The wavelength of the F₂ laser being exposure light is 157.624nm, the dioptric index of CaF₂ in the vicinity of 157.624 nm changes ina ratio of −2.6×10⁻⁶ per +1 pm of wavelength change and in a ratio of+2.6×10⁻⁶ per −1 pm of wavelength change. In other words, the dispersionof dioptric index (dn/dλ) of CaF₂ on the vicinity of 157.624 nm is2.6×10⁻⁶pm.

Therefore, in the first and second embodiments, the dioptric index ofCaF₂ to the wavelength 157.624 nm is 1.559238, the dioptric index ofCaF₂ to 157.624 nm+1 pm=157.625 nm is 1.5592354, and the dioptric indexof CaF₂ to 157.624 nm−1 pm=157.623 nm is 1.5592406. On the other hand,in the third embodiment, the dioptric index of CaF₂ to the wavelength157.624 nm is 1.559307, the dioptric index of CaF₂ to 157.624 nm+1 pm157.625 nm is 1.5593041, and the dioptric index of CaF₂ to 157.624 nm−1pm=157.623 nm is 1.5593093.

Furthermore, in the embodiments, if the height in a directionperpendicular to the optical axis is taken as y, the distance (amount ofsag) from a tangent plane at the vertex of aspherical surface to aposition on the aspherical surface at the height y along the opticalaxis as z, the vertex curvature radius as r, the conic coefficient as kand the n-order aspherical coefficient as C_(n), then the asphericalsurface is expressed by the following numerical formula (a).z=(y ² /r)/[1+{1−(1+κ)·y ² /r ²}^(1/2)]+C ₄ ·y ⁴ +C ₆ ·y ⁶ +C ₈ ·y ⁸ +C₁₀ ·y ¹⁰ +C ₁₂ ·y ¹² +C ₁₄ ·y ¹⁴  (a)

In the embodiments, a * sign is attached on the right side of surfaceno. on a lens surface which is formed into an aspherical shape.

[Embodiment 1]

FIG. 4 is a diagram showing the lens construction of a catadioptricoptical system (projection optical system PL) according to a firstembodiment. In the first embodiment, the present invention is applied toa projection optical system in which aberrations including chromaticaberrations are corrected for an exposure light with wavelength of157.624 nm±1 pm.

In the catadioptric optical system of FIG. 4, the first imaging opticalsystem G1 comprises a negative meniscus lens L11 having an asphericalconcave surface facing to the wafer side, a biconvex lens L12, abiconvex lens L13, a biconvex lens L14, a negative meniscus lens L15having a convex surface facing to the reticle side, a positive meniscuslens L16 having a concave surface facing to the reticle side, a positivemeniscus lens L17 having a concave surface facing to the reticle side, apositive meniscus lens L18 having a concave surface facing to thereticle side, a biconvex lens L19 and a positive meniscus lens L110having a convex surface facing to the reticle side in order from thereticle side.

The second imaging optical system G2 comprises a negative meniscus lensL21 having a concave surface facing to the reticle side, a negativemeniscus lens L22 having an aspherical concave surface facing to thereticle side and a concave reflecting mirror CM in order from thereticle side along the propagative route of light (i.e., the incidentside).

The third imaging optical system G3 comprises a biconvex lens L31 havingan aspherical convex surface facing to the facing reticle side, abiconvex lens L32, a biconvex lens L33, a biconcave lens L34, a positivemeniscus lens L35 having a convex surface facing to the reticle side, anaperture stop AS, a biconvex lens L36 having an aspherical convexsurface facing to the wafer side, a biconvex lens L37, a positivemeniscus lens L38 having a convex surface facing to the reticle side, apositive meniscus lens L39 having a convex surface facing to the reticleside, a biconcave lens L310 and a plano-convex lens L311 having a planesurface facing to the wafer side in order from the reticle side alongthe propagative route of light.

Values of data of the catadioptric optical system of the firstembodiment are identified in the following table (1). In the table (1),λ represents the wavelength of exposure light, β the projectionmagnification (magnification of whole system), NA the numerical apertureon the image side (wafer side), B the radius of image circle IF on waferW, A the off-axis quantity of effective exposure region ER, LX thedimension of effective exposure region ER along the X direction(dimension of long side), and LY the dimension of effective exposureregion ER along the Y direction (dimension of short side), respectively.

Moreover, the surface no. represents the order of surfaces from thereticle side along the propagative direction of light from the reticlesurface, being the object surface (first surface) to the wafer surface,being the image surface (second surface), r the curvature radius ofsurface (vertex curvature radius in the case of aspherical surface: mm),d the axial space of surface, i.e., surface distance (mm), and n thedioptric index to wavelength, respectively.

Furthermore, the surface distance d changes its sign with reflecteddegree. Therefore, the sign of the surface distance d is taken asnegative on the optical path from the first optical path folding mirror1 to the concave reflecting mirror CM and on the optical path from thesecond optical path folding mirror 2 to the image surface, and is takenas positive in other optical paths. Then, the curvature radius of aconvex surface facing to the reticle side is taken as positive and thecurvature radius of a concave surface facing to the reticle side istaken as negative in the first imaging optical system G1. On the otherhand, the curvature radius of a concave surface facing to the reticleside is taken as positive and the curvature radius of a convex surfacefacing to the reticle side is taken as negative in the third imagingoptical system G3. The curvature radius of a concave surface facing tothe reticle side (i.e., incident side) is taken as positive and thecurvature radius of a convex surface facing to the reticle side (i.e.,incident side) is taken as negative along the progression route of lightin the second imaging optical system G2.

TABLE 1 (Main data) λ = 157.624 nm β = −0.25 NA = 0.75 B = 14.6 mm A = 3mm LX = 22 mm LY = 6.6 mm (Data of optical members) Surface no. r d n(reticle surface) 129.131192  1 8233.14221 20.000000 1.559238 (lens L11) 2* 229.43210 8.970677  3 286.74048 31.000034 1.559238 (lens L12)  4−803.12188 1.000000  5 666.75874 33.633015 1.559238 (lens L13)  6−296.74142 1.000000  7 180.00000 38.351830 1.559238 (lens L14)  8−2028.08028 13.262240  9 201.14945 12.933978 1.559238 (lens L15) 10128.43682 221.621142  11* −127.65364 20.866949 1.559238 (lens L16) 12−120.00000 1.000000 13 −302.13109 23.424817 1.559238 (lens L17) 14−150.00000 1.000000 15 −1158.54680 23.049991 1.559238 (lens L18) 16−228.52501 1.000000 17 433.60390 22.934308 1.559238 (lens L19) 18−656.20038 1.000000 19 188.30389 21.335899 1.559238 (lens L110) 20563.10068 86.000000 21 ∞ −273.261089 (first optical path foldingmirror 1) 22 114.73897 −12.000000 1.559238 (lens L21) 23 453.07648−16.355803  24* 172.15013 −13.328549 1.559238 (lens L22) 25 395.88538−28.227312 26 162.85844 28.227312 (concave reflecting mirror CM) 27395.88538 −13.328549 1.559238 (lens L22)  28* 172.15013 16.355803 29453.07648 12.000000 1.559238 (lens L21) 30 114.73897 273.261089 31 ∞−94.835481 (second optical path folding mirror 2)  32* −774.94652−26.931959 1.559238 (lens L31) 33 275.96516 −1.000000 34 −376.08486−31.371246 1.559238 (lens L32) 35 388.08658 −1.000000 36 −219.25460−29.195314 1.559238 (lens L33) 37 4359.72825 −32.809802 38 505.14516−12.000000 1.559238 (lens L34) 39 −128.75641 −209.396172 40 −180.58054−24.481519 1.559238 (lens L35) 41 −331.81286 −14.336339 42 ∞ −30.366910(aperture stop AS) 43 −1502.56896 −24.392042 1.559238 (lens L36)  44*933.76923 −1.000000 45 −357.34412 −25.686455 1.559238 (lens L37) 462099.98513 −1.000000 47 163.08575 −32.557214 1.559238 (lens L38) 48−631.02443 −1.000000 49 −124.04732 −35.304921 1.559238 (lens L39) 50−639.72650 −18.536315 51 467.75212 −40.196625 1.559238 (lens L310) 52−616.22436 −1.000000 53 −95.47627 −38.068687 1.559238 (lens L311) 54 ∞−11.016920 (wafer surface) (Aspherical data) Surface 2 r = 229.43210 κ =0.000000 C₄ = 0.174882 × 10⁻⁷ C₆ = −0.593217 × 10⁻¹² C₈ = −0.194756 ×10⁻¹⁶ C₁₀ = 0.677479 × 10⁻²¹ C₁₂ = −0.212612 × 10⁻²⁵ C₁₄ = −0.320584 ×10⁻³⁰ Surface 11 r = −127.65364 κ = 0.000000 C₄ = −0.130822 × 10⁻⁷ C₆ =0.512133 × 10⁻¹² C₈ = 0.875810 × 10⁻¹⁶ C₁₀ = 0.138750 × 10⁻¹⁹ C₁₂ =−0.203194 × 10⁻²⁵ C₁₄ = 0.241236 × 10⁻²⁷ Surface 24 and Surface 28 (sameSurface) r = 172.15013 κ = 0.000000 C₄ = 0.293460 × 10⁻⁷ C₆ = −0.868472× 10⁻¹² C₈ = −0.848590 × 10⁻¹⁷ C₁₀ = −0.159330 × 10⁻²² C₁₂ = 0.868714 ×10⁻²⁶ C₁₄ = −0.116970 × 10⁻²⁹ Surface 32 r = −774.94652 κ = 0.000000 C₄= 0.253400 × 10⁻⁷ C₆ = −0.505553 × 10⁻¹² C₈ = 0.151509 × 10⁻¹⁶ C₁₀ =−0.433597 × 10⁻²¹ C₁₂ = 0.841427 × 10⁻²⁶ C₁₄ = 0.165932 × 10⁻³⁰ Surface44 r = 933.76923 κ = 0.000000 C₄ = −0.140105 × 10⁻⁷ C₆ = −0.779968 ×10⁻¹² C₈ = −0.148693 × 10⁻¹⁶ C₁₀ = 0.100788 × 10⁻²¹ C₁₂ = −0.251962 ×10⁻²⁵ C₁₄ = 0.104216 × 10⁻²⁹ (Corresponding values of conditions) β1 =−0.626 β2 = −0.919 β3 = −0.435 L1 = 335.3 mm L2 = 310.0 mm E = 484.8 mmD = 443.3 mm (1) |β2| = 0.919 (2) |L1 − L2| / |L1| = 0.076 (3) |β| /|β1| = 0.400 (4) |E − D| / |E| = 0.086

FIG. 5 are charts showing the lateral aberrations in the firstembodiment.

In the aberration charts, Y represents the image height, solid lines thewavelength 157.624 nm, broken lines 157.624+1 pm=157.625 nm and dashedlines 157.624−1 pm=157.623 nm, respectively.

As is evident from the aberration charts, it is generally known that thechromatic aberrations are well corrected for the exposure light with awavelength of 157.624±1 pm in the first embodiment.

[Embodiment 2]

FIG. 6 is a diagram showing the lens construction of a catadioptricoptical system (projection optical system PL) according to the secondembodiment. In the second embodiment, this invention is applied to aprojection optical system in which aberrations including chromaticaberrations are corrected for an exposure light with wavelength width of157.624 nm±1 pm similarly as in the first embodiment.

In the catadioptric optical system of FIG. 6, the first imaging opticalsystem G1 comprises a positive meniscus lens L11 having an asphericalconcave surface facing the wafer side, a negative meniscus lens L12having a concave surface facing the reticle side, a biconvex lens L13, abiconvex lens L14, a positive meniscus lens L15 having a convex surfacefacing the reticle side, a positive meniscus lens L16 having anaspherical concave surface facing the reticle side, a positive meniscuslens L17 having a concave surface facing the reticle side, a positivemeniscus lens L18 having a concave surface facing the reticle side, abiconvex lens L19 and a positive meniscus lens L110 having an asphericalconcave surface facing the wafer side in order from the reticle side.

The second imaging optical system G2 comprises a negative meniscus lensL21 having a concave surface facing the reticle side, a negativemeniscus lens L22 having an aspherical concave surface facing thereticle side and a concave reflecting mirror CM in order from thereticle side along the propagative route of light (i.e., the incidentside).

The third imaging optical system G3 comprises a biconvex lens L31 havingan aspherical convex surface facing the reticle side, a biconvex lensL32, a positive meniscus lens L33 having a convex surface facing thereticle side, a biconcave lens L34, a biconvex lens L35, an aperturestop AS, a negative meniscus lens L36 having an aspherical convexsurface facing the wafer side, a biconvex lens L37, a positive meniscuslens L38 having an aspherical convex surface facing the reticle side, apositive meniscus lens L39 having a convex surface facing the reticleside, a biconcave lens L310 and a plano-convex lens L311 having a planesurface facing the wafer side in order from the reticle side along thepropagative route of light (i.e., the incident side).

Values of data of the catadioptric optical system of the secondembodiment are identified in the following table (2). In the table (2),λ represents the wavelength of exposure light, β the projectionmagnification (magnification of whole system), NA the numerical apertureon the image side (wafer side), B the radius of image circle IF on waferW, A the off-axis quantity of effective exposure region ER, LX thedimension of effective exposure region ER along the X direction(dimension of long side), and LY the dimension of effective exposureregion ER along the Y direction (dimension of short side), respectively.

Moreover, surface no. represents the order of surfaces from the reticleside along the propagative direction of light from the reticle surfacebeing the object surface (first surface) to the wafer surface, being theimage surface (second surface), r the curvature radius of surface(vertex curvature radius in the case of aspherical surface: mm), d theaxial space of surface, i.e., surface distance (mm), and n the dioptricindex to wavelength, respectively.

Furthermore, the surface distance d changes its sign with reflecteddegree. Therefore, the sign of the surface distance d is taken asnegative on the optical path from the first optical path folding mirror1 to the concave reflecting mirror CM and on the optical path from thesecond optical path folding mirror 2 to the image surface, and is takenas positive in other optical paths. Then, the curvature radius of aconvex surface facing to the reticle side is taken as positive and thecurvature radius of a concave surface facing to the reticle side istaken as negative in the first imaging optical system G1. On the otherhand, the curvature radius of a concave surface surfacing to the articleside is taken as positive and the curvature radius of a convex surfacefacing to the article side is taken as negative in the third imagingoptical system G3. The curvature radius of a concave surface facing tothe reticle side (i.e., the incident side) is taken as positive and thecurvature radius of a convex surface facing to the reticle side (i.e.,the incident side) is taken as negative along the propagative route oflight in the second imaging optical system G2.

TABLE 2 (Main data) λ = 157.624 nm β = −0.25 NA = 0.75 B = 14.6 mm A = 3mm LX = 22 mm LY = 6.6 mm (Data of optical members) Surface no. r d n(reticle 74.237501 surface)  1 392.09887 18.011517 1.559238 (lens L11) 2* 1161.26854 22.550885  3 −197.82341 12.000000 1.559238 (lens L12)  4−320.24045 1.072412  5 4535.10509 27.582776 1.559238 (lens L13)  6−230.22207 1.003799  7 180.02979 31.376675 1.559238 (lens L14)  8−16797.46544 1.001727  9 120.09101 49.640624 1.559238 (lens L15) 10111.81156 146.176310  11* −147.64267 50.000000 1.559238 (lens L16) 12−120.00000 1.034195 13 −243.75596 21.927192 1.559238 (lens L17) 14−150.02545 1.001112 15 −355.46587 23.499758 1.559238 (lens L18) 16−170.06869 1.005485 17 380.97487 22.758028 1.559238 (lens L19) 18−1174.10533 1.018161 19 162.68954 24.816537 1.559238 (lens L110)  20*644.69642 86.000000 21 ∞ −275.440338 (first optical path foldingmirror 1) 22 116.98457 −20.000000 1.559238 (lens L21) 23 556.37904−19.644110  24* 165.29528 −22.001762 1.559238 (lens L22) 25 383.86012−26.835741 26 170.53370 26.835741 (concave reflect- ing mirror CM) 27383.86012 22.001762 1.559238 (lens L22)  28* 165.29528 19.644110 29556.37094 20.000000 1.559238 (lens L21) 30 116.98457 275.440338 31 ∞−106.008415 (second optical path folding mirror 2)  32* −8761.14467−25.535977 1.559238 (lens L31) 33 279.72974 −1.078193 34 −751.81935−30.303960 1.559238 (lens L32) 35 352.73770 −1.006012 36 −178.20333−35.675204 1.559238 (lens L33) 37 −1076.81270 −51.479106 38 1804.27479−28.746535 1.559238 (lens L34) 39 −120.27525 −169.573423 40 −250.01576−35.535941 1.559238 (lens L35) 41 521.40215 −35.714360 42 ∞ −24.295048(aperture stop AS) 43 152.18493 −24.773335 1.559238 (lens L36)  44*252.15324 −4.265268 45 −995.58003 −37.825368 1.559238 (lens L37) 46262.29146 −1.000000 47 −210.53420 −30.482411 1.559238 (lens L38) 48−8044.39654 −1.002741 49 −124.46496 −36.754604 1.559238 (lens L39) 50−627.72968 −9.489076 51 534.41093 −27.941522 1.559238 (lens L310) 52−9748.42213 −1.007391 53 −131.28658 −50.000000 1.559238 (lens L311) 54 ∞−12.503787 (wafer surface) (Aspherical data) Surface 2 r = 1161.26854 κ= 0.000000 C₄ = 0.141234 × 10⁻⁷ C₆ = 0.566669 × 10⁻¹² C₈ = 0.141094 ×10⁻¹⁶ C₁₀ = −0.504032 × 10⁻²⁰ C₁₂ = 0.747533 × 10⁻²⁴ C₁₄ = −0.400565 ×10⁻²⁸ Surface 11 r = −147.64267 κ = 0.000000 C₄ = 0.117741 × 10⁻⁶ C₆ =−0.764549 × 10⁻¹¹ C₈ = −0.441188 × 10⁻¹⁵ C₁₀ = 0.122309 × 10⁻¹⁸ C₁₂ =−0.114006 × 10⁻²² C₁₄ = 0.478194 × 10⁻²⁷ Surface 20 r = 644.69642 κ =0.000000 C₄ = 0.378434 × 10⁻⁷ C₆ = −0.751663 × 10⁻¹² C₈ = 0.247735 ×10⁻¹⁶ C₁₀ = −0.222239 × 10⁻²⁰ C₁₂ = 0.256558 × 10⁻²⁴ C₁₄ = −0.235204 ×10⁻²⁸ Surface 24 and surface 28 (same surface) r = 165.28528 κ =0.000000 C₄ = −0.236840 × 10⁻⁷ C₆ = 0.766085 × 10⁻¹² C₈ = −0.122244 ×10⁻¹⁶ C₁₀ = −0.209608 × 10⁻²¹ C₁₂ = 0.109632 × 10⁻²⁵ C₁₄ = −0.837618 ×10⁻³⁰ Surface 32 r = −8761.14467 κ = 0.000000 C₄ = 0.138366 × 10⁻⁷ C₆ =−0.162646 × 10⁻¹² C₈ = 0.264075 × 10⁻¹⁷ C₁₀ = 0.265565 × 10⁻²² C₁₂ =−0.494187 × 10⁻²⁶ C₁₄ = −0.786507 × 10⁻³¹ Surface 44 r = 252.15324 κ =0.000000 C₄ = 0.697432 × 10⁻⁸ C₆ = −0.714444 × 10⁻¹² C₈ = 0.747474 ×10⁻¹⁷ C₁₀ = −0.699569 × 10⁻²¹ C₁₂ = 0.228691 × 10⁻²⁵ C₁₄ = −0.160543 ×10⁻²⁹ (Corresponding values of conditions) β1 = −0.650 β2 = −0.885 β3 =−0.434 L1 = 347.8 mm L2 = 311.9 mm E = 453.1 mm D = 473.4 mm (1) |β2| =0.885 (2) |L1 − L2| / |L1| = 0.103 (3) |β| / |β1| = 0.385 (4) |E − D| /|E| = 0.045

FIG. 7 are charts showing the lateral aberrations in the secondembodiment.

In the aberration charts, Y represents the image height, solid lines thewavelength 157.624 nm, broken lines 157.624+1 pm=157.625 nm and dashedlines 157.624−1 pm=157.623 nm, respectively.

As is evident from the aberration charts, it is known that the chromaticaberrations are well corrected for the exposure light with a wavelengthof 157.624±1 pm in the second embodiment similar to in the firstembodiment.

[Embodiment 3]

In the first and second embodiments, both the first optical path foldingmirror 1 and the second optical path folding mirror 2 are constituted asfront surface reflecting mirrors. Moreover, in the first and secondembodiments, the angular widths of a beam incident into the reflectingplane of the first optical path of a folding mirror 1 and the reflectingplane of the second optical path of a folding mirror 2 increase inproportion to the numerical of aperture on the image side of thecatadioptric optical system. In this case, if the reflecting planes areformed of a dielectric multilayer film, the reflectivity changes withthe incident angle and the phase of a reflected wave disperses with theincident angle, thus it is difficult to ensure good angularcharacteristics. Therefore, it is preferable that the reflecting planesare formed of a metal film to obtain good angular characteristics, suchas a reflectivity nearly constant for a wide range of incident angles.However, the reduction of reflectivity arises if the metal is subjectedto irradiation of the F₂ laser in an atmosphere containing littleoxygen.

Accordingly, both the first optical path folding mirror 1 and the secondoptical path folding mirror 2 are constituted as rear (back) surfacereflecting mirrors in the third embodiment. More specifically, as shownin FIG. 13B, the first optical path folding mirror 1 is formed as aright-angle prism having a plane of incidence 1 a perpendicular to theoptical axis AX1 of a first imaging optical system G1, a reflectingplane 1 b inclined to the optical axis AX1 at an angle of 45° and aplane of emergence 1 c perpendicular to the optical axis AX2 of a secondimaging optical system G2. The second optical path folding mirror 2 isformed as a right-angle prism having a plane of incidence 2 aperpendicular to the optical axis AX2 of the second imaging opticalsystem G2, a reflecting plane 2 b inclined to the optical axis AX1 at anangle of 45° and a plane of emergence 2 c perpendicular to the opticalaxis AX3 of a third imaging optical system G3.

Moreover, the first optical path folding mirror 1 and the second opticalpath folding mirror 2 are integrally constituted as one optical pathfolding mirror FM. Then, the optical axis AX1 of the first imagingoptical system G1 and the optical axis AX3 of a third imaging opticalsystem G3 are so set up that they linearly extend and constitute asingle common optical axis, i.e., a reference optical axis AX.Furthermore, the intersection line of the rear (back) surface reflectingplane 1 b of first optical path folding mirror 1 and the rear (back)surface reflecting plane 2 b of second optical path folding mirror 2 areset up so that the optical axis AX1 of the first imaging optical systemG1, the optical axis AX2 of the second imaging optical system G2 and theoptical axis AX3 of the third imaging optical system G3 intersect at onepoint (reference point).

As described above, both the first optical path folding mirror 1 and thesecond optical path folding mirror 2 are constituted as rear (back)surface reflecting mirrors in the third embodiment.

Therefore, the rear (back) surface reflecting plane 1 b of the firstoptical path folding mirror 1 and the rear (back) surface reflectingplane 2 b of the second optical path folding mirror 2 are not subjectedto the irradiation of F₂ laser in an oxygen-containing atmosphere. As aresult, the reduction of reflectivity caused by the F₂ laser irradiationcan be avoided, even if the reflecting planes are formed of a metal filmto obtain good angular characteristics, such as a reflectivity that isnearly constant for a wide range of incident angles.

Moreover, if the reflecting planes (1 b, 2 b) and the transmittingplanes (1 a, 1 c, 2 a, 2 c) of the first optical path folding mirror 1and the second optical path folding mirror 2 are located in the vicinityof the formation position of a first intermediate image and a secondintermediate image, flaws, defects of coating, dust and the like onthese planes are transferred to the wafer surface. Furthermore, settinga reduced length from a reticle R to wafer W results in theminiaturization of the apparatus. The compact nature of the apparatus isalso favorable in transportation.

Accordingly, in the third embodiment, the first intermediate image isformed between the emergent plane 1 c of the first optical path foldingmirror 1 and a concave reflecting mirror CM. The second intermediateimage is formed between the concave reflecting mirror CM and incidentplane 2 a of the second optical path folding mirror 2. The thirdembodiment is specifically described below.

FIG. 13A is a diagram illustrating the lens construction of acatadioptric optical system (projection optical system PL) according tothe third embodiment. As in the first and second embodiments, thepresent invention is also applicable to a projection optical system inwhich aberrations including chromatic aberrations are corrected for anexposure light with a wavelength of 157.624 nm±1 pm in the thirdembodiment.

In the catadioptric optical system of FIG. 13A, the first imagingoptical system G1 comprises a positive meniscus lens L11 having anaspherical concave surface facing to the wafer side, a negative meniscuslens L12 having a concave surface facing to the reticle side, a biconvexlens L13, a positive meniscus lens L14 having a convex surface facing tothe reticle side, a positive meniscus lens L15 having a convex surfacefacing to the reticle side, a positive meniscus lens L16 having anaspherical concave surface facing to the reticle side, a positivemeniscus lens L17 having a concave surface facing to the reticle side, apositive meniscus lens L18 having a concave surface facing to thereticle side, a biconvex lens L19 and a positive meniscus lens L110having an aspherical concave surface to the wafer side in order from thereticle side.

The second imaging optical system G2 comprises a negative meniscus lensL21 having a concave surface facing to the reticle side, a negativemeniscus lens L22 having an aspherical concave surface facing to thereticle side and a concave reflecting mirror CM in order from thereticle side along the propagative route of light (i.e., the incidentside).

The third imaging optical system G3 comprises a biconvex lens L31 havingan aspherical convex surface facing the reticle side, a biconvex lensL32, a positive meniscus lens L33 having a convex surface facing to thereticle side, a biconcave lens L34, a biconvex lens L35, an aperturestop AS, a negative meniscus lens L36 having an aspherical convexsurface facing to the wafer side, a biconvex lens L37, a biconvex lensL38, a positive meniscus lens L39 having a convex surface facing to thereticle side, a negative meniscus lens L310 having a concave surfacefacing to the reticle side and a plano-convex lens L311 having a planesurface to the wafer side in order from the reticle side along thepropagative route of light.

Values of data of the catadioptric optical system of the thirdembodiment are identified in the following table (3). In the table (3),λ represents the wavelength of exposure light, β the projectionmagnification (magnification of whole system), NA represents thenumerical aperture on the image side (wafer side), B represents theradius of image circle IF on the wafer W, A represents the off-axisquantity of an effective exposure region ER, LX the dimension of theeffective exposure region ER along the X direction (dimension of longside), and LY represents the dimension of the effective exposure regionER along the Y direction (dimension of the short side), respectively.

Moreover, surface no. represents the order of surfaces from the reticleside along the propagative direction of light from the reticle surfacewhich is an object surface (first surface) to the wafer surface beingthe image surface (second surface), r the curvature radius of surface(vertex curvature radius in the case of the aspherical surface: mm), dthe axial space of surface, i.e., surface distance (nun), and n thedioptric index to the wavelength, respectively.

Furthermore, the surface distance d changes its sign with reflecteddegree. Therefore, the sign of the surface distance d is taken asnegative on the optical path from the first optical path folding mirror1 to the concave reflecting mirror CM and on the optical path from thesecond optical path folding mirror 2 to the image surface, and is takenas positive in other optical paths. Then, the curvature radius of convexsurface facing to the reticle side is taken as positive and thecurvature radius of the concave surface facing to the reticle side istaken as negative in the first imaging optical system G1. On the otherhand, the curvature radius of concave surface facing to the reticle sideis taken as positive and the curvature radius of convex surface facingto the reticle side is taken as negative in the third imaging opticalsystem G3. The curvature radius of concave surface directing to thereticle side (i.e., the incident side) is taken as positive and thecurvature radius of convex surface facing to the reticle side (i.e., theincident side) is taken as negative along the propagative route of lightin the second imaging optical system G2.

TABLE 3 (Main data) λ = 157.624 nm β = −0.25 NA = 0.75 B = 14.6 mm A = 3mm LX = 22 mm LY = 6.6 mm (Data of optical members) Surface no. r d n(reticle surface) 78.905334  1 342.16576 16.022696 1.559307 (lens L11) 2* 991.85390 17.753350  3 −219.16547 12.000000 1.559307 (lens L12)  4−320.00000 1.000000  5 2955.64579 26.141043 1.559307 (lens L13)  6−246.44297 1.000000  7 194.21831 26.260817 1.559307 (lens L14)  81329.96976 1.000000  9 107.60955 40.108611 1.559307 (lens L15) 10113.33032 159.676621  11* −148.84038 49.913127 1.559307 (lens L16) 12−120.00000 1.000000 13 −222.95345 20.859126 1.559307 (lens L17) 14−150.00000 1.000000 15 −401.55577 23.223530 1.559307 (lens L18) 16−183.82866 1.000000 17 521.59548 25.488040 1.559307 (lens L19) 18−467.35041 1.000000 19 163.47702 24.187152 1.559307 (lens L110)  20*493.47675 59.076923 21 ∞ 42.000000 1.559307 (incident plane of firstoptical path folding mirror 1) 22 ∞ −5.000000 1.559307 (reflecting planeof first optical path folding mirror 1) 23 ∞ −288.258092 (emergent planeof first optical path folding mirror 1) 24 117.68987 −20.000000 1.559307(lens L21) 25 494.06295 −20.317103  26* 162.15533 −23.222125 1.559307(lens L22) 27 424.56556 −30.146320 (concave reflecting mirror) 28174.51441 30.146320 29 424.56556 23.222125 1.559307 (lens L22)  30*162.15533 20.317103 31 494.06295 20.000000 1.559307 (lens L21) 32117.68987 288.258092 33 ∞ 5.000000 1.559307 (incident plane of secondoptical path folding mirror 2) 34 ∞ −42.000000 1.559307 (reflectingplane of second optical path folding mirror 2) 35 ∞ −75.000000 (emergentplane of second optical path folding mirror 2)  36* −4472.59851−25.928698 1.559307 (lens L31) 37 261.48119 −1.000000 38 −702.65223−25.574812 1.559307 (lens L32) 39 484.70684 −1.000000 40 −171.00841−36.095030 1.559307 (lens L33) 41 −824.20256 −52.106994 42 11305.93183−29.474446 1.559307 (lens L34) 43 −116.92116 −179.952947 44 −250.00000−35.678589 1.559307 (lens L35) 45 613.05439 −28.469304 46 ∞ −24.889346(aperture stop AS) 47 165.48519 −20.183765 1.559307 (lens L36)  48*279.53959 −1.000000 49 −1112.01574 −39.557019 1.559307 (lens L37) 50293.63544 −1.000000 51 −227.08614 −39.175338 1.559307 (lens L38) 523890.58196 −8.150754 53 −120.00000 −39.612810 1.559307 (lens L39) 54−519.19928 −10.442215 55 457.48024 −21.591566 1.559307 (lens L310) 562169.78959 −1.000000 57 −132.52125 −50.000000 1.559307 (lens L311) 58 ∞−12.499991 (wafer surface) (Aspherical data) Surface 2 r = 991.85390 κ =0.000000 C₄ = 0.117208 × 10⁻⁷ C₆ = 0.310236 × 10⁻¹² C₈ = 0.401356 ×10⁻¹⁷ C₁₀ = −0.265435 × 10⁻²⁰ C₁₂ = 0.412618 × 10⁻²⁴ C₁₄ = −0.238346 ×10⁻²⁸ Surface 11 r = −148.84038 κ = 0.000000 C₄ = 0.637735 × 10⁻⁷ C₆ =−0.462907 × 10⁻¹¹ C₈ = −0.137097 × 10⁻¹⁵ C₁₀ = 0.475629 × 10⁻¹⁹ C₁₂ =−0.370236 × 10⁻²³ C₁₄ = 0.833198 × 10⁻²⁸ Surface 20 r = 493.47675 κ =0.000000 C₄ = 0.280809 × 10⁻⁷ C₆ = −0.360031 × 10⁻¹² C₈ = 0.929800 ×10⁻¹⁷ C₁₀ = −0.100162 × 10⁻²⁰ C₁₂ = 0.116050 × 10⁻²⁴ C₁₄ = −0.979417 ×10⁻²⁹ Surface 26 and Surface 30 (same surface) r = 162.15533 κ =0.000000 C₄ = −0.235140 × 10⁻⁷ C₆ = −0.709685 × 10⁻¹² C₈ = −0.957183 ×10⁻¹⁷ C₁₀ = −0.947024 × 10⁻²² C₁₂ = 0.274134 × 10⁻²⁶ C₁₄ = −0.469484 ×10⁻³⁰ Surface 36 r = −4472.59851 κ = 0.000000 C₄ = 0.108255 × 10⁻⁷ C₆ =−0.135832 × 10⁻¹² C₈ = 0.188102 × 10⁻¹⁷ C₁₀ = −0.163001 × 10⁻²² C₁₂ =0.128506 × 10⁻²⁶ C₁₄ = −0.312367 × 10⁻³⁰ Surface 48 r = 279.53959 κ =0.000000 C₄ = 0.176353 × 10⁻⁷ C₆ = −0.889127 × 10⁻¹² C₈ = 0.132824 ×10⁻¹⁶ C₁₀ = −0.701110 × 10⁻²¹ C₁₂ = 0.104172 × 10⁻²⁵ C₁₄ = −0.327893 ×10⁻³⁰ (Corresponding values of conditions) β1 = −0.650 β2 = −0.865 β3 =−0.445 L1 = 320.8 mm L2 = 365.2 mm E = 466.7 mm D = 455.6 mm (1) |β2| =0.865 (2) |L1 − L2| / |L1| = 0.138 (3) |β| / |β1| = 0.385 (4) |E − D| /|E| = 0.024

FIG. 14 are charts illustrating the lateral aberrations in the thirdembodiment.

In the aberration charts, Y represents the image height, the solid linesrepresent the wavelength 157.624 nm, the broken lines representwavelength 157.624+1 pm=157.625 nm and the dashed lines representwavelength 157.624−1 pm=157.623 nm, respectively.

As is evident from the aberration charts, it is known that the chromaticaberrations can be corrected for the exposure light with a wavelength of157.624±1 pm in the third embodiment as similarly corrected in the firstand second embodiments.

As described above, in the first to third embodiments, the image side,having a NA of 0.75, can be provided and the image circle with radius of14.6 mm, in which the aberrations beginning with the chromaticaberrations are corrected, can be provided on the wafer. Therefore, ahigh resolution of about 0.1 μm can be obtained in addition to providinga rectangular effective exposure region that is approximately 22 mm×6.6mm.

Moreover, in the first to third embodiments, an off-axis quantity A assmall as about 3 mm can be set up on the wafer W because the secondimaging optical system G2 has a nearly unit (equal) magnification β2 andthe optical path separation is provided in the vicinity of the twointermediate images formed by a mutual approach. As a result, arectangular effective exposure region approximately as large as 22mm×6.6 mm can be provided in the image circle that is as small as about14.6 mm in radius. Thus, an optical system superior in aberrationcorrection, miniaturization, optical adjustment, mechanical design, andin cost of manufacturing can be obtained.

Furthermore, in the first to third embodiments, the reticle R and thewafer W can be arranged in parallel to each other and along a planeperpendicular to the direction of gravity (i.e., horizontal plane). Allthe lenses constituting the first imaging optical system G1 and thethird imaging optical system G3 can be arranged in parallel along asingle optical axis AX of the direction of gravity because the firstimaging optical system G1 and the third imaging optical system G3 areprovided in an upright position along the common reference optical axisAX. Accordingly, the reticle R, the wafer W and most of lensesconstituting the projection optical system PL (91% in number for all theembodiments) are parallel, and are not subject to asymmetricaldeformation caused by their own weight. Likewise, optical adjustment,mechanical design and high resolution are advantageously ensured.

Additionally, in the first to third embodiments, the intersection lineof the reflecting planes of the first optical path folding mirror 1 andthe second optical path folding mirror 2 are set up so that the opticalaxis AX1 of the first imaging optical system G1, the optical axis AX2 ofthe second imaging optical system G2 and the optical axis AX3 of thethird imaging optical system G3 intersect at one point (referencepoint). The first optical path folding mirror 1 and the second opticalpath folding mirror 2 are integrally formed as a triagonal prism memberin which the top side and the bottom side are shaped into right angledisosceles triangles, i.e., one optical path folding mirror FM. As aresult, the stability of the optical system increases. The opticaladjustment and mechanical design are simple because it is possible toposition the three optical axes AX1–AX3 and the ridge lines of theoptical path folding mirror FM in connection at one reference point. Inaddition, the high-accuracy optical adjustment is simple and the opticalsystems have higher stability because the optical axis AX2 of the secondimaging optical system G2 is set up so that it is perpendicular to thereference optical axis AX which is the common optical axis of the firstimaging optical system G1 and the third imaging optical system G3.

Furthermore, in the first, second and third embodiments, theintersection line of reflecting planes of the first optical path foldingmirror 1 and the second optical path folding mirror 2 are set up so thatthe optical axis AX1 of the first imaging optical system G1, the opticalaxis AX2 of the second imaging optical system G2 and the optical axisAX3 of the third imaging optical system G3 intersect at one point(reference point) as described above. As shown in the alternative, FIGS.15 and 16, illustrate an intersection line of reflecting planes of thefirst optical path folding mirror 1 and the second optical path foldingmirror 2 which is not located at the intersection of the optical axisAX1 of the first imaging optical system G1, the optical axis AX2 of thesecond imaging optical system G2 and the optical axis AX3 of the thirdimaging optical system G3.

FIG. 15 is a schematic block diagram of a catadioptric optical systembased on modification example 1. In the catadioptric optical systemshown in FIG. 15, the optical axis AX1 of the first imaging opticalsystem G1 and the optical axis AX3 of the third imaging optical systemG3 are coincident. The intersection line of reflecting planes of thefirst optical path folding mirror 1 and the second optical path foldingmirror 2 is located on the side opposite to the concave mirror CM forthe optical axis AX1 of the first imaging optical system G1 and theoptical axis AX3 of the third imaging optical system G3.

FIG. 16 is a schematic block diagram of a catadioptric optical systembased on modification example 2. In the catadioptric optical systemshown in FIG. 16, the optical axis AX1 of the first imaging opticalsystem G1 and the optical axis AX3 of the third imaging optical systemG3 are coincident. The intersection line of reflecting planes of thefirst optical path folding mirror 1 and the second optical path foldingmirror 2 is located on the side of concave mirror CM for the opticalaxis AX1 of the first imaging optical system G1 and the optical axis AX3of the third imaging optical system G3.

Moreover, in previous examples, the optical axis AX1 of the firstimaging optical system G1 and the optical axis AX2 of the second imagingoptical system G2 are orthogonal and the optical axis AX2 of the firstimaging optical system G2 and the optical axis AX3 of the third imagingoptical system G3 are orthogonal. However, they may also be constitutedso that the optical axis AX1 of the first imaging optical system G1, theoptical axis AX2 of the second imaging optical system G2 and the opticalaxis AX3 of the third imaging optical system G3 are non-orthogonal. See,e.g., modification example 3 shown in FIG. 17.

Furthermore, in previous examples, the optical axis AX1 of the firstimaging optical system G1 and the optical axis AX3 of the third imagingoptical system G3 are coincident. However, a construction in which theoptical axis AX1 of the first imaging optical system G1 and the opticalaxis AX3 of the third imaging optical system G3 shift in parallel toeach other is also possible. See, e.g., modification example 4 shown inFIG. 18. In the modification example 4 shown in FIG. 18, theintersection line of the first optical path folding mirror 1 and thesecond optical path folding mirror 2 is not coincident with the opticalaxis AX1 of the first imaging optical system G1 and the optical axis AX3of the third imaging optical system G3. The intersection line of thefirst optical path folding mirror 1 and the second optical path foldingmirror 2 may also be constituted so that it is coincident with theintersection of optical axis AX1 of the first imaging optical system G1and optical axis AX2 of the second imaging optical system G2 or theintersection of optical axis AX2 of the second imaging optical system G2and optical axis AX3 of the third imaging optical system G3.

Additionally, in previous examples, the optical axis AX1 of the firstimaging optical system G1 and the optical axis AX3 of the third imagingoptical system G3 are in parallel to (coincident with) each other (theaxis AX1 of the first imaging optical system G1 and the axis AX2 of thesecond imaging optical system G2 are made orthogonal and the axis AX2 ofthe second imaging optical system G2 and the axis AX3 of the thirdimaging optical system G3 are made orthogonal). However, a constructionin which the optical axis AX1 of the first imaging optical system G1 andthe optical axis AX3 of the third imaging optical system G3 are notparallel to each other is also possible. See, e.g., modification example5 shown in FIG. 19. In the modification example 5 shown in FIG. 19, theintersection line of reflecting planes of the first optical path foldingmirror 1 and the second optical path folding mirror 2 is set up so thatit intersects with the optical axis AX1 of the first imaging opticalsystem G1, the optical axis AX2 of the second imaging optical system G2and the optical axis AX3 of the third imaging optical system G3 at onepoint (reference point). However, they may also be constituted so as notto intersect at the reference point. See, e.g., the modification example2 shown in FIG. 15 and FIG. 16.

Next, a detailed construction of the projection exposure apparatus ofthe embodiment shown in FIG. 2 is described below.

FIG. 8 is a diagram showing the general construction of the projectionexposure apparatus of the embodiment shown in FIG. 2. FIG. 9 is anenlarged diagram which shows a portion of to the illumination opticalsystem of the projection exposure apparatus of FIG. 8. FIG. 10 is anenlarged diagram which shows a portion of the projection optical systemof the projection exposure apparatus of FIG. 8.

First, a detailed construction of the portion of the illuminationoptical system IL of FIGS. 8–9 is described.

The projection exposure apparatus is provided with a F₂ laser lightsource 100, e.g., 156.624 nm in wavelength used in a natural oscillation(almost half width 1.5 pm). However, the application of an ArF excimerlaser light source of about 193 nm, a KrF excimer light source of about248 mn, an Ar₂ laser light source and the like can also be used in thepresent invention. The light source 100 may be arranged on the lowerfloor where the main body of the exposure apparatus. An exclusive area(footprint) of main body of the exposure apparatus can be decreased andan influence of vibrations on the main body of the exposure apparatuscan also be reduced.

A light from the light source 100 is led into the inside of a firstillumination system casing 110 via a beam matching unit (BMU) 101. Thefirst illumination system casing 110 receives movable optical elementsinside it and supports them by a supporting member 210 on a base plate200. The beam matching unit 101 contains a movable mirror matching anoptical path between the light source 100 and an the main body of theexposure apparatus. Moreover, the optical path between the light source100 and the beam matching unit 101 is optically connected by a cylinder(tube) 102, and an optical path between the beam matching unit 101 andthe first illumination system casing 110 is optically connected by acylinder (tube) 103. Nitrogen or a rare gas (inert gas), such as heliumand the like, is filled in the optical path of the cylinder 102 andcylinder 103.

The light led into the inside of the first illumination system casing110 passes through a micro fly's eye lens 111 (an optical systemequivalent to a first fly's eye lens), and lens groups 112, 113constituting an afocal zoom relay optical system (a both sidetelecentric zoom optical system), and then comes to a turret 114 forloading plural diffraction array optical elements or dioptric arrayoptical elements. The micro fly's eye lens 111 is an optical systemcomprising many fine (micro) lenses having a positive dioptric power andarranged vertically and horizontally in a dense arrangement. Generally,the micro fly's eye lens 111 is constituted, e.g., by applying anetching treatment to a parallel plane glass plate to form the fine lensgroups. Diffraction array optical elements disclosed in U.S. Pat. No.5,850,300 can be used as the diffraction array optical elements, anddioptric array optical elements disclosed in WO 99/49505 (EP 1,069,600),wherein the elements are formed on one substrate by an etching techniquecan be used as the dioptric array optical elements.

U.S. Pat. No. 5,850,300 and WO 99/49505 (EP 1,069,600) are incorporatedherein by reference.

In the plural diffraction array optical elements or the dioptric arrayoptical elements supported by the turret 114, a light passing throughone diffraction, or dioptric, array optical element positioned in theilluminating optical path incides into a micro fly's eye lens 117 via afocal zoom optical system (115, 116). A front focal point of the afocalzoom optical system (115, 116) is positioned in the vicinity of thediffraction array optical element or the dioptric array optical elementof the turret 114. The micro fly's eye lens 117 is an optical systemequivalent to a second fly's eye lens. The micro fly's eye lens 117includes many fine lenses which are much finer than fly's eye lenses andproduces a large wave front dividing effect. Thus, an illuminatingaperture stop is not provided on its emergent side (back focus plane).The micro fly's eye lens 117 is constituted by a pair of micro fly's eyelenses at a space along the optical axis, and an aspherical surface mayalso be introduced into its refracting surface. This constructionresults in the suppression of the occurrence of a coma aberration in themicro fly's eye lens 117 and suppresses the occurrence of unevenilluminance distribution on the reticle. Furthermore, a turret type stopprovided with a iris stop, a annular aperture and a quadrupole aperturemay also be arranged in the vicinity of rear focal plane of the microfly's eye lens 117.

The light exiting from the micro fly's eye lens 117 illuminates amovable blind mechanism 120 superimposed via a condenser optical system(118, 119). The front focal position of the movable blind mechanism 120is positioned in the vicinity of position of a surface light source(plural light source images) formed by the micro fly's eye lens 117. Themovable blind mechanism 120 is provided with a fixed illumination fieldstop (fixed blind) 121 with a slit aperture and a movable blind 122 forvarying the width of an illumination field region in the scanningdirection. The movable blind 122 allows for a decrease in the movingstroke of a reticle stage in the scanning direction and a decrease inthe width of shading zone (frame) of reticle. Moreover, the fixed blind121 is arranged together with the reticle. The construction of themovable blind mechanism 120 is disclosed in Japan Kokai 4-196513 (U.S.Pat. No. 5,473,410).

U.S. Pat. No. 5,473,410 is incorporated herein by reference.

The light passing through the movable blind mechanism 120 emits from thefirst illumination system casing 110 and is led to the inside of asecond illumination system casing 130. An imaging optical system of theilluminating field stop is provided for reimaging the illuminating fieldstop on the reticle by a given enlargement magnification. The lensgroups (131–134) and optical path folding mirrors (135, 136), whichconstitute the illumination field stop imaging optical system must notbe used for a vibration source because they are fixed to the secondillumination system casing 130. The second illumination system casing130 is supported by a supporting member 211 on the base plate 200. Themagnification factor of the imaging optical system of illuminating fieldstop may be equal to (unity) or a reduced ratio.

Driving units (142, 143) for driving the lens groups (112, 113) of theafocal zoom relay optical system in the direction of optical axis arearranged in the first illumination system casing 110. The driving units(142, 143) are mounted to the outer side of the first illuminationsystem casing 110 to prevent the contamination in the illuminatingoptical path. A driving unit 144 for rotationally driving the turret 114and driving units 145, 146 for driving the lens groups (115, 116)constituting the afocal zoom relay optical system in the direction ofoptical axis are mounted to the outer side of the first illuminationsystem casing 110 to prevent the contamination in the illuminatingoptical path.

Driving units (147, 148) for driving the lens groups (118, 119)constituting the condenser optical system in the direction of opticalaxis, rotating at least one lens group with an axis perpendicular to theoptical axis as center and moving (offsetting) the other lens group inthe direction perpendicular to the optical axis are mounted to the outerside of the first illumination system casing 110. The focal length ofthe condenser optical system can be changed and in its turn the size ofan illumination region formed on a wafer and the illumination NA(numerical aperture) can be properly changed on the reticleindependently of each other by movement of the lens groups (118, 119) inthe direction of optical axis. Controls of slanted illuminance (inclinedilluminance distribution) on the wafer surface and slanted (inclined)telecentricity are obtained by the rotation and offset of the lensgroups (118, 119). An illuminance control symmetrical to the opticalaxis on the wafer surface is obtained by moving one lens group in thedirection of the optical axis separately from a previous illuminationfield variable.

Furthermore, a tube 151 for allowing nitrogen or a rare gas (inert gas),such as helium and the like, to flow into the inside of the firstillumination system casing 110, and a tube 152 for allowing nitrogen ora rare gas (inert gas), such as helium and the like, to discharge fromthe first illumination system casing 110 are arranged on the outer sidethereof. Valves (161, 162) for controlling the gas inflow rate/outflowrate are arranged at the tubes (151, 152), respectively. If the inertgas is helium, the tubes (151, 152) are connected to a heliumrecovery/regeneration unit, e.g., disclosed in Japan Kokai 11-219902 (WO99/25010, EP 1,030,351).

EP 1,030,351 is incorporated herein by reference.

A tube 153 for allowing nitrogen or a rare gas (inert gas), such ashelium and the like, to flow into the inside of the second illuminationsystem casing 130 and a tube 154 for allowing nitrogen or a rare gas(inert gas), such as helium and the like, to discharge from the secondillumination system casing 130 are arranged on the outer side thereof.Valves (163, 164) for controlling the gas inflow rate/outflow rate arearranged at the tubes (153, 154), respectively. If the inert gas ishelium, the tubes (153, 154) are also connected to the previouslymentioned helium recovery/regeneration unit.

A bellows 170 is provided for connecting the first illumination systemcasing 110 and the movable blind mechanism 120. Another bellows 171 isprovided for connecting the movable blind mechanism 120 and the secondillumination system casing 130. The bellows 170, 171 are formed of amaterial which has a certain degree of flexibility and rigidity that isnot so great as to deform and to ensure less degassing, e.g., a metal ora material given by coating a rubber or resin with aluminum and thelike.

In the illumination optical system IL arranged as above, a beam incidentfrom the laser light source 100 to the micro fly's eye lens 111 isdivided two-dimensionally by many fine lenses, and one light sourceimage is formed on the back focal plane of each fine lens, respectively.The beam from the many light source images (surface light sources)formed at the back focal plane of the micro fly's eye lens 111 incidesinto one diffraction array optical element, e.g., a diffraction opticalelement for annular modified illumination, arranged in the illuminationoptical path by the turret 114 via the afocal zoom relay optical system(112, 113). The beam converted to rings via the diffraction opticalelement for annular modified illumination forms a annular illuminationfield at its back focal plane and in its turn at the incident plane ofthe micro fly's eye lens 117 via the afocal zoom optical system (115,116).

The beam inciding into the micro fly's eye lens 117 is dividedtwo-dimensionally by many fine lenses, and a light source image isformed on the back focal plane of each fine lens where the beam incides,respectively. Thus, many annular light sources (secondary surface lightsources) are provided (same as the illumination field formed by the beaminciding into the micro fly's eye lens 117). The light from thesesecondary surface light sources is subjected to a condensing action ofthe condenser optical system (118, 119) and then illuminates a givenplane optically together with the reticle R superimposed. Thus, arectangular illumination field similar to the shape of each fine lensconstituting the micro fly's eye lens 117 is formed on the fixed blind121 arranged at this given plane. The beam passing through the fixedblind 121 and the movable blind 122 of the movable blind mechanism 120is subjected to a condensing action of the imaging optical system ofillumination field stop (131–134) and then illuminates the reticle Rwith a given formed pattern evenly and superimposed.

Here, modified illuminations like annular modified illumination ormultipole (e.g., dipole (two-eyed), quadrupole (four-eyed), octapole(eight-eyed) and so on) modified illumination and conventional circularillumination can be imposed by switching the diffraction array opticalelements or the dioptric array optical elements arranged in theillumination optical path by the turret 114. In the case of the annularmodified illumination, for example, both the size (outer diameter) andshape (annular ratio) of a annular secondary light source can be changedby changing the magnification of the afocal zoom relay optical system(112, 113). Moreover, the outer diameter of the annular secondary lightsource can be changed by changing the focal length of the focal zoomoptical system (115, 116) without changing its annular ratio. Only theannular ratio of the annular secondary light source can be changed byproperly changing the focal length of the focal zoom optical system(115, 116) without changing the outer diameter of the light source.

A detailed construction of a portion of the projection optical system PLis described hereafter, with reference to FIG. 8 and FIG. 10.

The described projection exposure apparatus is horizontally arranged onthe floor of a clean room and is provided with the base plate (framecaster) 200 which becomes the datum of the apparatus. Plural supportingmembers (221, 222) are vertically arranged on the base plate 200. Onlytwo supporting members are shown in FIGS. 8 and 10, but four supportingmembers are vertically arranged in practice. Three supporting membersmay also be used.

Anti-vibration units (231, 232) for isolating vibrations from the floorat a micro G level are mounted to the supporting members (221, 222),respectively. In the anti-vibration units (231, 232), an air mount withcontrollable internal pressure and an electromagnetic actuator (e.g.,voice coil motor) are arranged in parallel or in series. Thetransmission of vibrations from the floor to a column 240 for holdingthe projection optical system is reduced by the action of theanti-vibration units (231, 232). A plurality of supporting members (251,252) for supporting a reticle stage fixed plate 301 are verticallyarranged on the column 240. In FIGS. 8 and 10, only two supportingmembers (251, 252) are shown, but they are actually four members (mayalso be three members).

The described projection exposure apparatus is provided with a reticlestage RS float supporting on the reticle base fixed plate 301. Thereticle stage RS is constituted so that the reticle R can be linearlydriven in the Y-axis direction with a large stroke, and also can bedriven in the X-axis, Y-axis directions and θ_(z) (direction of rotationaround the Z axis) with a little driven amount.

Moreover, a reticle stage RS in which a reticle stage and a reticle basebetween the reticle base fixed plate and the reticle stage is provided.The reticle base may be shifted so as to keep a momentum in a directionreverse to the direction of movement of the reticle stage. Such areticle stage is disclosed, e.g., in Japan Kokai 11-251217 (U.S. patentapplication Ser. No. 260,544 filed on Mar. 2, 1999). Moreover, a reticlestage holding two reticles along the Y-axis direction (scanningdirection) as shown in Japan Kokai 10-209039 (EP 855,623) and JapanKokai 10-214783 (EP 951,054) may also be used as the reticle stage RS.

U.S. patent application Ser. No. 260,544, EP 855,623 and EP 951,054 areincorporated herein by reference.

A reticle interferometer RIF is arranged on the reticle base fixed plate301 for measuring the position and the amount of movement of the reticlestage RS in the XY direction. One end of the reticle stage RS is areflecting plane, which is a moving (measuring) mirror of the reticleinterferometer RIF. A reticle chamber partition 310 for forming a spacewhere an optical path in the vicinity of the reticle R is sealed with aninert gas (nitrogen, helium and the like) is arranged on the reticlebase fixed plate 301. A door for moving the reticle in or out of areticle stocker (not shown) may be provided. A reticle pool room fortemporarily receiving the reticle before moving the reticle into thereticle chamber and replacing the internal gas with an inert gas isarranged by adjoining it to the reticle chamber.

A bellows 321 for connecting the reticle chamber partition 310 and thesecond illumination system casing 130 is arranged. The material of thebellows 321 is similar to the previously mentioned bellows (170, 171). Atube 331 for allowing nitrogen or a rare gas (inert gas), such as heliumand the like, to flow into the reticle chamber and a tube 332 forallowing nitrogen or a rare gas (inert gas), such as helium and thelike, to discharge from the reticle chamber are arranged on the outerside of the reticle chamber partition 310. If the inert gas is helium,and the tubes (331, 332) may also be connected to the previouslymentioned helium recovery/regeneration unit.

Valves (341, 342) for controlling the gas inflow rate/outflow rate arearranged at the tubes (331, 332), respectively. Moreover, a bellows 351for connecting the reticle base fixed plate 301 and the projectionoptical system is arranged. The material of the bellows 351 is similarto the previously mentioned bellows 321. Thus, the space in the vicinityof the reticle R is sealed by the action of the reticle chamberpartition and the bellows (321, 351).

The projection exposure apparatus is provided with a wafer stage fixedplate 401. The wafer stage fixed plate 401 is horizontally supported onthe base plate 200 by the action of anti-vibration units (411, 412) forisolating vibrations from the floor at a micro G level. In theanti-vibration units (411, 412), an air mount with controllable internalpressure and an electromagnetic actuator (e.g., voice coil motor) may bearranged in parallel or in series. The wafer stage WS is movable in theXY direction and is floatably loaded on the wafer stage fixed plate 401.

The wafer stage WS comprises a Z-leveling stage for inclination in thebiaxial direction of θ_(x) (direction of rotation around the X axis) andθ_(y) (direction of rotation around the Y axis) and movable in theZ-axis direction and a θ stage for making it movable in the θ_(z)(direction of rotation around the Z axis) direction. For example, awafer stage disclosed in Japan Kokai 8-63231 (GB 2,290,658) can be usedas the wafer stage WS. Moreover, two wafer stages may also be arrangedas described in Japan Kokai 10-163097, Japan Kokai 10-163098, JapanKokai 10-163099, Japan Kokai 10-163100, Japan Kokai 10-214783 (EP951,054), or Japan Kokai 10-209039 (EP 855,623), WO 98/28665 or WO98/40791.

GB 2,290,658, EP 855,623, EP 951,054, WO 98/28665 and WO 98/40791 areincorporated herein by reference.

A wafer table (wafer holder) WT for loading the wafer by vacuum suctionand/or electrostatic suction is arranged on the wafer stage WS. A waferchamber partition 411 for forming a space where an optical path in thevicinity of the wafer W is sealed with an inert gas (nitrogen, heliumand the like) is arranged on a wafer stage fixed plate 401. A door formoving the wafer in or out of a reticle stocker (not shown) may beprovided. A reticle spare room for temporarily receiving wafers beforemoving the wafers into the wafer chamber and replacing the internal gaswith an inert gas is arranged by adjoining it to the wafer chamber.

A sensor column SC is fixed to a lens barrel (or the column 240) of theprojection optical system. An alignment sensor 421 for opticallymeasuring the position of an alignment mark on the wafer W in the XYtwo-dimensional direction is provided, an auto-focus leveling sensor 422for detecting the position of the wafer in the Z-axis direction (opticalaxis direction) and the inclinations of θ_(x), θ_(y) and θ_(z) intriaxial direction and a wafer interferometer WIF for measuring theposition and amount of movement of the wafer table WT in the XYdirection are mounted to the sensor column SC.

At least one of a FIA (Field Image Alignment) system which the markposition by illuminating an alignment mark on the wafer with a lighthaving a broad wavelength region, such as a halogen lamp and the like,and then processing this mark image, a LSA (Laser Step Alignment) systemwhich measures the mark position by irradiating a laser light on a markand then using a light diffracted and scattered by the mark and a LIAsystem (Laser Interferometric Alignment) which detects the positionalinformation of mark from its phase by irradiating a laser light withonly a little different frequency on an alignment mark like diffractiongratings from two directions and then interfering two diffraction lightsgenerated by the mark with each other is suitable for the alignmentsensor 421.

The auto-focus leveling sensor 422 detects whether the surface of waferto be exposed coincides (focuses) with the image surface of theprojection optical system. An auto-focus leveling sensor which detectsZ-axis direction positions of detection points in plural locationsarranged into a matrix is suitable for the auto-focus leveling sensor422. In this case, the detection points in plural locations are arrangedin a range including the slit-like exposure region formed by theprojection optical system.

The wafer interferometer WIF measures the position and the amount ofmovement of the wafer stage in the XY direction. One end of the waferstage WS becomes a reflecting plane. The reflecting plane becomes amoving (measuring) mirror of the wafer interferometer WIF. A tube 431for allowing nitrogen or a rare gas (inert gas), such as helium and thelike, to flow into the wafer chamber and a tube 432 for allowingnitrogen or a rare gas (inert gas), such as helium and the like, todischarge from the wafer chamber are arranged on the outer side of thewafer chamber partition 411.

If the inert gas is helium, the tubes (431, 432) can be connected to thepreviously mentioned helium recovery/regeneration unit. Valves (441,442) for controlling the gas inflow rate/outflow rate are arranged atthe tubes (431, 432), respectively. Moreover, a bellows 451 forconnecting the wafer chamber partition 411 and the sensor column SC isvertically arranged on the wafer stage fixed plate 401. The material ofthe bellows 451 is same, e.g., as the previously mentioned bellows 321.Thus, the space in the vicinity of the wafer W is sealed by the actionof the wafer chamber partition 411 and the bellows 451.

The described projection exposure apparatus is provided with a parallelplane plate L1 for covering a purge space in the projection opticalsystem. The projection optical system is provided with a first imagingoptical system for forming a primary image (a first intermediate image)of the pattern of the reticle R. The first imaging optical system iscomposed of lenses (L2–L7: corresponding to L11–L110 in the firstimaging optical system of FIG. 2). The parallel plane plate L1 and thelenses (L2–L7) are received in divided barrels (501–507), respectively.Connection techniques between the divided barrels are disclosed in,Japan Kokai 7-86152 (U.S. Pat. No. 5,638,223). U.S. Pat. No. 5,638,223is incorporated herein as reference.

The parallel plane plate L1 is held by a cell 511. The cell 511 holdsthe parallel plane plate L1 so as to be put between the top surface andthe under surface of the parallel plane plate L1. The held locations areplural locations (3 locations or more) in the circumferential direction(θ_(z) direction) of the parallel plane plate L1. An air (gas)-tightstructure is disposed between the parallel plane plate L1 and the cell511. The lenses (L2–L7) are held by cells (512–517). The cells (512–517)hold the lenses (L2–L7) so as to be put between the top surface and thebottom surface of rims arranged at the periphery of the lenses (L2–L7).The held locations are plural locations (3 locations or more) in thecircumferential direction of the lenses.

The divided barrels (501–507) and the cells (511–517) are connected byframes 521–527. Apertures for allowing an inert gas (helium) to passinside of the projection optical system are arranged in the frames521–527 at plural locations along its circumferential (tangential)direction. An air (gas)-tight structure is disposed between the frame521 and the divided barrel 501.

In the first imaging optical system, an actuator 532 for moving the lensL2 in the optical axis direction (Z direction) and inclining it in theθ_(x), θ_(y) directions is arranged. This actuator 532 is arranged at apitch of 1200 in three locations which is equal distant from the opticalaxis and spaced in the circumferential direction (θ_(z) direction). Alinear motor, piezoelectric element, cylinder mechanism driven by apressure fluid or gas and the like can be used as the actuator 532. Ifthe driven amount of actuator 532 is the same, the lens L2 can be movedin the optical axis direction. The lens L2 can be inclined in the θ_(x),θ_(y) direction by setting it up so that the driven amount of theactuator 532 in three different locations is different, respectively.Actuators 533, 535, 536, 537 operate similar to actuator 532.

In the first imaging optical system, an actuator 543 for moving the lensL3 in the XY plane is arranged. These actuator 543 is between theactuator 533 and a frame 523 and is arranged at a pitch of 120° in threelocations which are equal distant from the optical axis and different inthe circumferential direction (θ_(z) direction). A linear motor,piezoelectric element, cylinder mechanism driven by a pressure fluid orgas and the like can be used as the actuator 543. A tube 551 forallowing helium to flow into the inside of the projection optical systemis arranged in the divided barrel 511. This tube 551 may also beconnected to the previously mentioned helium recovery/regeneration unit.A valve 561 for controlling the gas inflow rate is arranged at the tube551.

The projection optical system is provided with an optical path foldingmirror FM integrally formed by a first optical path folding mirror and asecond optical path folding mirror. The optical path folding mirror FMcan be formed, e.g., by vapor deposition of a metal, such as aluminumand the like, on two side faces in a triagonal prism member in which thetop surface and the lower surface are in the shape of right angledisosceles triangles. A dielectric multilayer film may also be vapordeposited in place of a metal film. As the materials of dielectricmultilayer film, metal fluorides such as aluminum fluoride, cryolite,chiolite, lithium fluoride, sodium fluoride, barium fluoride, calciumfluoride, magnesium fluoride, yttrium fluoride, ytterbium fluoride,neodymium fluoride, gadolinium fluoride, lanthanum fluoride, osmiumfluoride, strontium fluoride and the like can be used. A construction inwhich a dielectric multilayer film is arranged on a metal film, such asaluminum and the like, may also be used. The dielectric multilayer filmfunctions as a protection coat for preventing the metal film fromoxidation. This dielectric multilayer film functions to correct thephase difference between P polarization and S polarization caused by areflecting light from the metal film so as to decrease it and to correcta difference in phase difference between P polarization and Spolarization due to the incident angle (emergent angle) (angularcharacteristic of PS phase difference) so as to homogenize it in adesirable range of incident angles. If a phase difference between Ppolarization and S polarization exists, this is undesirable because theimaging positions of an image due to the P polarization and an image dueto the S polarization deviate and cause the deterioration of imagequality on the imaging surface; thus a desirable resolution is notobtained. Moreover, two plane mirrors may be kept so as toperpendicularly intersect to each other in place of forming the firstand the second optical path folding mirrors on one member. In this case,it is considered that the two plane mirrors are kept adjustably, e.g.,by a technique disclosed in Japan Kokai 2000-28898, which isincorporated herein by reference.

The projection optical system is also provided with a second imagingoptical system for forming a second intermediate image (a secondaryimage of the pattern) nearly equal to the first intermediate image insize, based on a light from the first intermediate image formed by thefirst imaging optical system. The second imaging optical system isprovided with lenses (L8, L9: corresponding to negative lenses L21, L 22in the second imaging optical system G2 of FIG. 2) and a concavereflecting mirror CM. SiC or a composite of SiC and Si can be used asthe material of the concave reflecting mirror CM. It is preferable tocoat the entire concave reflecting mirror CM with SiC fordegassification prevention. The reflecting surface of the concavereflecting mirror CM is formed by vapor deposition of metals, such as,e.g., aluminum and the like. A dielectric multi-layer film may also bevapor deposited in place of a metal film. In this case, as the materialsof dielectric multilayer film, metal fluorides such as aluminumfluoride, cryolite, chiolite, lithium fluoride, sodium fluoride, bariumfluoride, calcium fluoride, magnesium fluoride, yttrium fluoride,ytterbium fluoride, neodymium fluoride, gadolinium fluoride, lanthanumfluoride, osmium fluoride, strontium fluoride and the like can be used.A construction in which a dielectric multilayer film is arranged on ametal film, such as aluminum and the like, may also be used. Thedielectric multilayer film functions as a protection coat for preventingthe metal film from oxidation. This dielectric multilayer film enablesthe metal film to have a correcting function so as to decrease the phasedifference between P polarization and S polarization caused by areflecting light from the metal film. The correcting function nearlyhomogenizes a difference in phase difference between P polarization andS polarization caused by the incident angle (reflection angle) (angularcharacteristic of PS phase difference) in a desirable range of incidentangle. If the phase difference between P polarization and S polarizationexists, this is undesirable because the imaging positions of an imagedue to the P polarization and an image due to the S polarization deviateand cause the deterioration of image quality on the imaging surface anda desirable resolution is not obtained. The materials of the concavereflecting mirror can include ULE or Be. If Be is used, it is preferablethat the whole concave reflecting mirror CM is coated with SiC and thelike.

The optical folding mirror FM and the lens L8 are contained by a dividedbarrel 601, the lens L9 is contained by a divided barrel 602 and theconcave reflecting mirror CM is contained in a divided barrel 603. Aholding member 610 for holding the optical folding mirror FM is mountedto the divided barrel 601. A mechanism for adjusting the position of theoptical folding mirror FM (first and second optical folding mirrors) inthe θ_(x), θ_(y), θ_(z) directions and its position in the XYZdirections may be arranged between this holding member 610 and thedivided barrel 601.

The lenses (L8, L9) of the second imaging optical system are supportedby supporting members (611, 612). Supporting members disclosed in JapanKokai 6-250074 and Japan Kokai 11-231192 are suitable for thesesupporting members (611, 612). The concave reflecting mirror CM of thesecond imaging optical system is supported by a supporting member 613.Supporting members disclosed in Japan Kokai 6-250074, Japan Kokai11-231192 are suitable for this supporting member 613 and areincorporated herein by reference.

The projection optical system is further provided with a third imagingoptical system for forming a final image (a reduced image of thepattern) on the wafer based on a light from the second intermediateimage formed by the second imaging optical system. The third imagingoptical system is provided with lenses (L10–L13: corresponding to thelenses L31–L311 in the third imaging optical system G3 of FIG. 2) and avariable aperture stop unit AS. The lens L110 is contained by a dividedbarrel 701 and the lens L11 is contained by a divided barrel 702. Aflange FL supported by a column 240 is arranged in the divided barrel702. Techniques for connection of the flange FL and the column 240, forexample, are disclosed in Japan Kokai 6-300955 (U.S. Pat. No. 5,576,895)and Japan Kokai 11-84199 are applicable. A sensor column SC is mountedto the flange FL. U.S. Pat. No. 5,576,895 is incorporated herein byreference.

The variable aperture stop AS is contained by a divided barrel 703 andthe lenses (L12, L13) are contained by divided barrels (704, 705). TheL10–L13 are supported by cells (711–712, 714–715), respectively. Thestructure of the cells (711–712, 714–715) is similar to that of the cell512. An air (gas)-tight structure is disposed between the lens L13 andthe cell 715 in the cell 715.

In the third imaging optical system, frames (721–722, 724–725) forconnecting the divided barrels (701–702, 704–705) and the cells(711–712, 714–715) are arranged. Apertures for allowing an inert gas(helium) to flow into the inside of the projection optical system arearranged in plural locations along their circumferential direction inthe frames (721–722, 724–725). An air (gas)-tight structure is disposedbetween the cell 715 and the divided barrel 705.

In the third imaging optical system, actuators (731–732, 734) for movingthe lens (L10–L12) in the optical axis direction and inclining theimaging optical system in the θ_(x), θ_(y) directions are arranged.These actuators (731–732, 734) have construction similar to the actuator532. A tube 751 for allowing helium to discharge from the projectionoptical system is arranged in the divided barrel 705. This tube 751 isalso connected to the previously mentioned helium recovery/regenerationunit. A valve 761 for controlling the gas inflow rate is arranged at thetube 751.

Next, the embodiments of a manufacturing process wherein the previouslymentioned exposure apparatus and an exposure method are used in thelithographic process are described below.

FIG. 11 is a diagram showing the flowchart of a manufacturing process(semiconductor chips such as IC or LSI and the like, liquid crystalpanel, CCD, thin-film magnetic head, micro-machine and so on). As shownin FIG. 11, design step 201 illustrates a function/property design(e.g., circuit design of semiconductor devices and the like) of devices(micro-devices) and a pattern design for obtaining the functions arealso made (design step). Successively, a mask (reticle) for forming adesigned circuit pattern is prepared in a step 202 (mask preparationstep). Alternatively, wafers can be manufactured with a material such assilicon and the like in a step 203 (wafer manufacture step).

Next, in the step 204 (wafer processing step), actual circuits and thelike are formed on the wafers by using wafers prepared in step 201 andstep 203 according to a lithographic technique and the like as describedlater. Subsequently, in the step 205, the device assembly is conductedby using wafers processed in step 204. Such processes include, e.g., adicing process, a bonding process and a packaging process (chipenclosure) and so on in step 205 according to demand.

Finally, in a step 206 (inspection step), inspections conducted include,e.g., an action confirmation test, a durability test and so on for thedevices prepared in step 205. After processing, the devices arecompleted and shipped.

FIG. 12 is a diagram showing one example of the wafer processing of step204 in FIG. 11 for semiconductor devices. In FIG. 12, the wafer surfaceis oxidized in a step 211 (oxidation step). An insulating film is formedon the wafer surface in a step 212 (CVD step). Electrodes are formed onthe wafers by vapor deposition in a step 213 (electrode formation step).An ion is implanted into the wafers in a step 214 (ion implantationstep). Steps 211 through step 214 constitute a pretreatment process ofthe wafer processing, and are selected and executed according to thedemand called for by the processing steps.

In the wafer processing steps, if the above pretreatment process hasbeen completed, a post-treatment process as follows is executed. In thepost-treatment process, first, a sensitizer is applied to wafers in astep 215 (resist formation step). Successively, a circuit pattern ofmask given by the lithographic system (exposure apparatus) and exposuremethod described above is transferred on wafers in a step 216 (exposurestep). Next, the exposed wafers are developed in step 217 (developmentstep), and exposed members in a part, except for an area where theresist remains, are removed by etching in step 218 (etching step).After, the etching is finished, any unnecessary resist is removed instep 219 (resist removal step).

Circuit patterns are formed on the wafers by repeating the abovementioned pretreatment and post-treatment process steps.

If the manufacturing method of this embodiment is applied, devices witha high integrated level of about 0.1 μm in minimum line width can beproduced with sufficient yield. The method applies the use of theexposure apparatus and the exposure method described above in theexposure process (step 216), thereby improving the resolving power of anexposure light in the vacuum ultraviolet region and producing highaccuracy exposure control.

Moreover, in this embodiment form, the tubes connected to the inside ofthe projection optical system are disposed in two locations. The numberof tubes is not limited to only two locations. For example, a number oftubes (inflow port/outflow outlet) corresponding to respective lenschambers (spaces between optical members) may be arranged. The pressurefluctuation of the gas in the projection optical system and theillumination optical system can be suppressed to a predetermined value.At this time, an allowable value of the pressure fluctuation is set upsuch that the value of the projection optical system more tight thanthat of the illumination optical system.

Furthermore, the pressure change of an inert gas filled or circulatedamong optical elements of the illumination system and projection opticalsystem is detected, and optical elements for aberration correction(L2–L3, L5–L7, L10–L12 in FIG. 8 through FIG. 10) may also be drivenbased on the detected result. Such a technique is disclosed, e.g., inWO99/10917 (EP 1,020,897). EP 1,020,897 is incorporated herein byreference.

Additionally, it is preferable that the concentrations and/or the totalamount of light-absorbing substances (gases such as oxygen (O₂), carbondioxide (CO₂) and the like, water vapor (H₂O) and so on, are given assubstances absorbing exposure beams and light-absorbing substances forthe F₂ laser light of wavelength 157 μm) in the optical path of theillumination optical system, the optical path in the reticle chamber,the optical path in the projection optical system and the optical pathin the wafer chamber are controlled independently of each other. Forexample, allowable concentrations and an allowable total amount of thelight-absorbing substances can be variably set up because the waferchamber and the reticle chamber have short optical paths. Thus, theopen/close mechanisms of the reticle chamber are simplified and contactwith the outside air or mix-in of light-absorbing substances is avoidedbecause of the reticle exchange and the wafer exchange. Allowableconcentrations and an allowable total amount of the light-absorbingsubstances are harshly set up in response to the illumination opticalsystem having a long optical path.

An F₂ laser can be incorporated in this embodiment which can include,nitrogen, rare gases such as helium (He), neon (Ne), argon (Ar) and thelike as a permeable gas having a wavelength of 157 nm. Helium gas isparticularly superior in high permeability, stability of imagingcharacteristic of optical system and cooling property since its heatconductivity is about 6 times greater than that of nitrogen and itsfluctuation of dioptric index to pressure change is about ⅛greater thanthat of nitrogen gas. In this embodiment, the gas in the wafer chamberand the reticle chamber which fills the optical path of theinterferometers (wafer interferometer, reticle interferometer) and theinside of the projection optical system can be helium. And, the gas inthe optical path of the illumination optical system can be nitrogen gasin order to reduce the running cost. The gas used in the optical path ofthe illumination optical system can also be helium and the gas in thewafer chamber, the reticle chamber, and inside the projection opticalsystem can be nitrogen.

The following photopermeable optical materials constituting theillumination optical system and the projection optical system that canbe used include: lenses, parallel plane plates, micro fly's eye lensesand diffraction optical elements. In addition, fluorite (CaF₂), modifiedquartzs such as F-doped silica glass, F- and H-doped silica glass,OH-containing silica glass, F-doped and OH-containing silica glass andthe like can also be used. The photopermeable optical materialsconstituting the illumination optical system and the projection opticalsystem may also include the previously mentioned modified quartz. In theF-doped silica glass, the fluorine concentration is preferably 100 ppmor more, and more preferably in a range of 500 ppm–30,000 ppm. In theF-doped and H-doped silica glass, the hydrogen concentration ispreferably 5×10¹⁸ molecules/cm³ or less, and more preferably 1×10¹⁸molecules/cm³ or less. In the OH-containing silica glass, theconcentration of OH group is preferably in a range of 10 ppm–100 ppm. Inthe F-doped and OH-containing silica glass, the fluorine concentrationis preferably 100 ppm or more and the concentration of OH group ispreferably lower than the fluorine concentration. In this embodiment,the concentration of OH group is preferably in a range of 10 ppm–20 ppm.

When an image is formed by using a region free of the optical axis ofthe projection optical system, as in the present embodiment, anillumination optical system disclosed in Japan Kokai 2000-21765 (U.S.patent application Ser. No. 340,236 filed on Jul. 1, 1999) can be usedas the illumination optical system. U.S. patent application Ser. No.340,236 is incorporated hereby by reference.

Moreover, in this embodiment, a portion of the optical element in theoptical elements constituting the projection optical system isinclinable to the θ_(x), θ_(y) directions and/or movable in the XYplane. The optical elements may also be rotatably arranged in adirection of rotation (θ_(z) direction in the first and third imagingoptical systems) with the optical axis as the center by forming theoptical surfaces (refractive surfaces/reflecting surfaces) of theseoptical elements so as to have different powers in the meridionaldirections perpendicular to each other (dioptric plane/reflecting plane)of the optical elements (conducting an astigmatic surface processing).This arrangement results in correct asymmetrical aberrations such as anastigmatic difference on the optical axis (center astigmatism) of theprojection optical system, or a rhombic distortion of that.

For example, a construction in which an actuator and a driving axis aredisposed along the tangential direction of the circumstance of the frameis arranged between a frame and a divided barrel such that the frame isdriven to the divided barrel in the θ_(z) direction. It is preferablethat the actuator is equal distant from the optical axis and arranged ina plurality of different locations at an equal-angle pitch in thecircumferential direction (θ_(z) direction). A mechanism for rotatingoptical members with an astigmatic surface is disclosed in Japan Kokai8-327895 (U.S. Pat. No. 5,852,518). U.S. Pat. No. 5,852,518 isincorporated herein by reference.

Furthermore, a purge space may also be formed on the outside of thepurge space of the illumination optical system and/or purge space of theprojection optical system. In this case, the allowable concentration andallowable total amount of light-absorbing substance of the purge spaceson the outside are set up more unexacting than the purge spaces on theinner side (the purge space of the illumination optical system and/orthe purge space of the projection optical system).

Additionally, a parallel plane plate is arranged on the wafer side ofthe lens on the wafer side of the projection optical system. Theparallel plane plate may also be provided as a cover to the purge spaceof the projection optical system similar to the reticle side.

In addition to the F₂ laser light that supplies a pulse light having awavelength of 157 nm as provided for in this embodiment, implementingvarious other light sources is also possible. For example, the followinglight sources can be implemented a KrF excimer laser light supplying alight of wavelength 248 nm, and an ArF excimer laser light supplying alight of wavelength 193 m, and an Ar₂ laser light supplying a light ofwavelength 126 nm. A harmonic wave given by amplifying a laser lightwith a single wavelength in the infrared region oscillated from a DFBsemiconductor laser or a fiber laser or in the visible region with anEr-doped (or both Er-and Yb-doped) fiber amplifier that converts thelight source to an ultraviolet light with a nonlinear optical crystalmay also be used.

The present invention is applicable not only to micro-devices such as,semiconductor devices and the like, but also to an exposure apparatusfor transferring circuit patterns from a mother reticle to a glasssubstrate, or a silicon wafer and the like, to manufacture a reticle ora mask used in, e.g., a light exposure apparatus an EUV exposureapparatus, an X-ray exposure apparatus and an electron ray exposureapparatus and the like. Transmitting reticles are commonly used in theexposure apparatus using DUV (deep ultraviolet) or VUV (vacuumultraviolet) light and the like. Silica glass, F-doped silica glass,fluorite, magnesium fluoride, or quartz crystal and the like are used asthe reticle substrate. In a proximity-mode X-ray exposure apparatus andan electron ray exposure apparatus and the like, transmitting masks(stencil mask, membrane mask) are used. A silicon wafer and the like isused as the mask substrate. Such exposure apparatus are disclosed in WO99/34255 (EP 1,043,625), WO 99/50712 (U.S. patent application Ser. No.661,396 filed on Sep. 13, 2000), WO 99/66,370, Japan Kokai 11-194479,Japan Kokai 2000-12453, Japan Kokai 2000-29202 and so on. EP 1,043,625,U.S. patent application Ser. No. 661,396 and WO 99/66,370 areincorporated herein by reference.

The present invention is applicable not only to the manufacture ofsemiconductor devices, but also to an exposure apparatus which cantransfer device patterns onto a glass plate which are used in themanufacture of displays including liquid crystal display devices. Anexposure apparatus which transfers device patterns onto a ceramic waferand which are used in the manufacture of thin-film magnetic head, and anexposure apparatus used in the manufacture of image pickup devices suchas CCD and the like, and so on can also be applied.

The above-described present invention applies the scanning step mode ofoperation. The present invention is also applicable to a step-and-repeatmode reduction projection exposure apparatus in which mask patterns aretransferred to a substrate in a static state of the mask and thesubstrate. The substrate is then moved in successive steps.

An aperture stop is arranged in the third imaging optical system in thepreviously mentioned embodiment. The aperture stop may also be arrangedin the first imaging optical system. A field stop may also be arrangedin at least one of the position of the intermediate image between thefirst imaging optical system and the second imaging optical system, andthe position of the intermediate image between the second imagingoptical system and the third imaging optical system.

The projection magnification of the catadioptric projection opticalsystem is given as a reduction ratio in previously mentioned embodiment.However, the projection magnification is not limited to the reductionratio (magnification), it can also be an equal ratio (an unitmagnification) or an enlargement ratio (magnification). For example, ifthe projection magnification is the enlargement ratio, the opticalsystem can be arranged so that a light is incided from the side of thethird imaging optical system, a primary image of the mask or the reticleis formed by the third imaging optical system, a secondary image isformed by the secondary imaging optical system and a tertiary image isformed by the first imaging optical system on a substrate such as waferand the like.

As described above, in the catadioptric optical system, the projectionexposure apparatus and the exposure method including the optical systemof the previously mentioned embodiments, the optical adjustment andmechanical design are improved. The aberrations beginning with chromaticaberrations can be fully corrected. For example, a resolution of about0.1 μm or less can be achieved by using a light with a wavelength of 180nm or less in the vacuum ultraviolet wavelength region. Particularly, inthe previous embodiments, the optical path separation is disposed in thevicinity of two intermediate images which are formed by a mutualapproach of the second imaging optical system having a nearly equal(unit) magnification. Thus, the present invention provides for a smalldistance in the exposure region from the optical axis, i.e., the offsetquantity, and is favorable in aberration correction, miniaturization,optical adjustment, mechanical design, manufacturing cost and so on.

The previously mentioned embodiments provide for improvements in theoverlay accuracy of each exposure (each relay) and the synchronizationaccuracy of the reticle and the wafer because the reticle surface andthe wafer surface are parallel to each other and perpendicular to thedirection of gravity. The optical adjustment and the mechanical designis simple since there are only two optical axes. Thus, a transmissionreflecting film having a low absorption and a high extinction ratio, ahigh-accuracy plate with a ¼wavelength and a prism with homogeneity arenot required and stray light caused by a transmission reflecting planeand the like also do not occur because transmission reflecting planeslike a semi-transparent mirror or a polarizing beam splitter are notused. Also, because the reticle surface and the wafer surface areparallel to each other and perpendicular to the direction of gravity.

Moreover, in the manufacturing method of micro-devices using theprojection exposure apparatus and the exposure method of the previouslymentioned embodiments, improved micro-devices can be manufactured viathe projection optical system in which the optical adjustment andmechanical design are simple. In addition, aberrations beginning withchromatic aberrations can be fully corrected and a high resolution ofabout 0.1 μm or less can be achieved.

While the invention has been described with reference to preferredembodiments thereof, it is to be understood that the invention is notlimited to the preferred embodiments or constructions. To the contrary,the invention is intended to cover various modifications and equivalentarrangements. In addition, while the various elements of the preferredembodiments are shown in various combinations and configurations, whichare exemplary, other combinations and configurations, including more,less or only a single element, are also within the spirit and scope ofthe invention.

1. A catadioptric optical system forming a reduced image of a firstsurface onto a second surface comprising: a first imaging opticalsubsystem which is arranged in an optical path between the first surfaceand the second surface and includes a dioptric imaging optical system toform a first intermediate image of the first surface; a first foldingmirror which is arranged in the vicinity of a position of forming thefirst intermediate image to deflect a beam prior to or after theposition where the first intermediate image is formed; a second imagingoptical subsystem which is arranged in an optical path between the firstfolding mirror and the second surface and which forms a secondintermediate image with a magnification factor nearly equal to the firstintermediate image in the vicinity of a position of forming the firstintermediate image based on the beam from the first intermediate image,the second imaging optical subsystem includes a concave reflectingmirror and at least one negative lens; a second folding mirror which isarranged in the vicinity of a position of forming the first intermediateimage to deflect a beam prior to or after the position where the secondintermediate image is formed; and a third imaging optical subsystemwhich is arranged in an optical path between the second imaging opticalsubsystem and the second surface and includes a dioptric imaging opticalsystem to form the reduced image onto the second surface based on thebeam from the second intermediate image, wherein the catadioptricoptical system is a telecentric optical system on both sides of thefirst surface and the second surface.
 2. The catadioptric optical systemof claim 1, wherein a reflecting surface of the first folding mirror anda reflecting surface of the second folding mirror are positioned so thatthey do not overlap spatially.
 3. The catadioptric optical system ofclaim 2, wherein all lenses constituting the first imaging opticalsubsystem and all lenses constituting the third imaging opticalsubsystem are arranged along a single optical axis.
 4. The catadioptricoptical system of claim 3, wherein a magnification factor β2 of thesecond imaging optical subsystem satisfies the following condition:0.082<|β2|<1.20.
 5. The catadioptric optical system of claim 4, whereinthe following condition is satisfied:|L 1−L 2|/|L 1|<0.15, where a first distance between the firstintermediate image and the concave reflecting mirror in the secondimaging optical subsystem along the optical axis is defined as L1, and asecond distance between the second intermediate image and the concavereflecting mirror in the second imaging optical subsystem along theoptical axis is defined as L2.
 6. The catadioptric optical system ofclaim 5, wherein the following condition is satisfied:0.20<|β|/|β1|<0.50, where a magnification of the catadioptric opticalsystem is defined as β, and a magnification of the first imaging opticalsubsystem is defined as β1.
 7. The catadioptric optical system of claim6, wherein the following condition is satisfied:|E−D|/|E|<0.24, where a distance between a surface of the first imagingoptical subsystem on a most image side and an exit pupil position alongthe optical axis is defined as E, and a distance by air conversion fromthe surface of the first imaging optical subsystem on the most imageside to the concave reflecting mirror in the second imaging opticalsubsystem along the optical axis is defined as D.
 8. The catadioptricoptical system of claim 7, wherein: the first intermediate image isformed in an optical path between the first folding mirror and thesecond imaging optical subsystem; and the second intermediate image isformed in an optical path between the second imaging optical subsystemand the second folding mirror.
 9. The catadioptric optical system ofclaim 8, wherein: 85% of the number of lenses in all lenses constitutingthe catadioptric optical system are arranged along the single opticalaxis.
 10. The catadioptric optical system of claim 9, wherein: anintersection line of an extension plane of the reflecting surface of thefirst folding mirror and an extension plane of the reflecting surface ofthe second folding mirror is set up so that an optical axis of the firstimaging optical subsystem, an optical axis of the second imaging opticalsubsystem and an optical axis of the third imaging optical subsystemintersect at one point.
 11. The catadioptric optical system of claim 10,wherein: the second imaging optical subsystem has at least two negativelenses.
 12. The catadioptric optical system of claim 11, wherein: thefirst folding mirror has a back surface reflecting mirror for reflectinga beam from the first imaging optical subsystem to the second imagingoptical subsystem; and the second folding mirror has a back surfacereflecting mirror for reflecting a beam from the second imaging opticalsubsystem to the third imaging optical subsystem.
 13. The catadioptricoptical system of claim 12, wherein: the catadioptric optical systemforms the reduced image on a position deviating from a position ofreference in an optical axis of the catadioptric optical system on thesecond surface.
 14. The catadioptric optical system of claim 1, wherein:a plurality of lenses constituting the first imaging optical subsystemand a plurality of lenses constituting the third imaging opticalsubsystem are arranged along a single optical axis.
 15. The catadioptricoptical system of claim 1, wherein a magnification β2 of the secondimaging optical subsystem satisfies the following condition:0.82<|β2|<1.20.
 16. The catadioptric optical system of claim 15, whereinthe following condition is satisfied:|L 1−L 2|/|L 1|<0.15, where a first distance between the firstintermediate image and the concave reflecting mirror in the secondimaging optical subsystem along the optical axis is defined as L1, and asecond distance between the second intermediate image and the concavereflecting mirror in the second imaging optical subsystem along theoptical axis is defined as L2.
 17. The catadioptric optical system ofclaim 1, wherein the following condition is satisfied:|L 1−L 2|/|L 1|<0.15, where a first distance between the firstintermediate image and the concave reflecting mirror in the secondimaging optical subsystem along the optical axis is defined as L1, and asecond distance between the second intermediate image and the concavereflecting mirror in the second imaging optical subsystem along theoptical axis is defined as L2.
 18. The catadioptric optical system ofclaim 1, wherein the following condition is satisfied:0.20<|β|β1|<0.50, where a magnification of the catadioptric opticalsystem is defined as β, and a magnification of the first imaging opticalsubsystem is defined as β1.
 19. The catadioptric optical system of claim1, wherein the following condition is satisfied:|E−D|/|E|<0.24, where a distance between a surface of the first imagingoptical subsystem on a most image side and an exit pupil position alongthe optical axis is defined as E, and a distance by air conversion fromthe surface of the first imaging optical subsystem on the most imageside to the concave reflecting mirror in the second imaging opticalsubsystem along the optical axis is defined as D.
 20. The catadioptricoptical system of claim 1, wherein: the first intermediate image isformed in an optical path between the first folding mirror and thesecond imaging optical subsystem; and the second intermediate image isformed in an optical path between the second imaging optical subsystemand the second folding mirror.
 21. The catadioptric optical system ofclaim 1, wherein: 85% of the number of lenses in all lenses constitutingthe catadioptric optical system are arranged along the single opticalaxis.
 22. The catadioptric optical system of claim 1, wherein anintersection line of an extension plane of a reflecting surface of thefirst folding mirror and an extension plane of a reflecting surface ofthe second folding mirror is set up so that an optical axis of the firstimaging optical subsystem, an optical axis of the second imaging opticalsubsystem and an optical axis of the third imaging optical subsystemintersect at one point.
 23. The catadioptric optical system of claim 1,wherein the second imaging optical subsystem has at least two negativelenses.
 24. The catadioptric optical system of claim 1, wherein: thefirst folding mirror has a back surface reflecting surface forreflecting a beam from the first imaging optical subsystem to the secondimaging optical subsystem; and the second folding mirror has a backsurface reflecting surface for reflecting a beam from the second imagingoptical subsystem to the third imaging optical subsystem.
 25. Thecatadioptric optical system of claim 1, wherein: the catadioptricoptical system forms the reduced image in a position deviating from aposition of a reference optical axis of the catadioptric optical systemon the second surface.
 26. A catadioptric optical system forming areduced image of a first surface onto a second surface comprising: afirst imaging optical subsystem with a first optical axis, which isarranged in an optical path between the first surface and the secondsurface and includes a dioptric imaging optical system; a second imagingoptical subsystem with a concave reflecting mirror and a second opticalaxis, which is arranged in an optical path between the first imagingoptical subsystem and the second surface; and a third imaging opticalsubsystem with a third optical axis, which is arranged in an opticalpath between the second imaging optical subsystem and the second surfaceand includes a dioptric imaging optical system, wherein the firstoptical axis and the second optical axis intersect with each other andthe second optical axis and the third optical axis intersect with eachother, and wherein the catadioptric optical system is a telecentricoptical system on both sides of the first surface and the secondsurface.
 27. The catadioptric optical system of claim 26, furthercomprising: a first reflection surface arranged in an optical pathbetween the first imaging optical subsystem and the second imagingoptical subsystem; and a second reflection surface arranged in anoptical path between the second imaging optical subsystem and the thirdimaging optical subsystem.
 28. The catadioptric optical system of claim27, wherein a first intermediate image is formed in an optical pathbetween the first reflection surface and the second imaging opticalsubsystem by the first imaging optical subsystem, and a secondintermediate image is formed in an optical path between the secondimaging optical subsystem and the second reflection surface by thesecond imaging optical subsystem.
 29. The catadioptric optical system ofclaim 28, wherein the following condition is satisfied:|L 1−L 2|/|L 1|<0.15, where a first distance between the firstintermediate image and the concave reflecting mirror in the secondimaging optical subsystem along the optical axis is defined as L1, and asecond distance between the second intermediate image and the concavereflecting mirror in the second imaging optical subsystem along theoptical axis is defined as L2.
 30. The catadioptric optical system ofclaim 26, wherein a magnification factor β2 of the second imagingoptical subsystem satisfies the following condition:0.082<|β2|<1.20.
 31. The catadioptric optical system of claim 30,wherein the following condition is satisfied:0.20<|β|/|β1|<0.50, where a magnification of the catadioptric opticalsystem is defined as β, and a magnification of the first imaging opticalsubsystem is defined as β1.
 32. The catadioptric optical system of claim31, wherein the following condition is satisfied:|E−D|/|E|<0.24, where a distance between a surface of the first imagingoptical subsystem on a most image side and an exit pupil position alongthe optical axis is defined as E, and a distance by air conversion fromthe surface of the first imaging optical subsystem on the most imageside to the concave reflecting mirror in the second imaging opticalsubsystem along the optical axis is defined as D.
 33. The catadioptricoptical system of claim 30, wherein the second imaging optical subsystemhas at least two negative lenses.
 34. The catadioptric optical system ofclaim 26, wherein 85% of the number of lenses in all lenses constitutingthe catadioptric optical system are arranged along a single opticalaxis, and wherein the first optical axis and the third optical axis formthe single optical axis.
 35. The catadioptric optical system of claim26, wherein the catadioptric optical system forms the reduced image in aposition deviating from a position of a reference optical axis of thecatadioptric optical system on the second surface.
 36. A catadioptricoptical system forming a reduced image of a first surface onto a secondsurface comprising: a first imaging optical subsystem with a firstoptical axis, which is arranged in an optical path between the firstsurface and the second surface and includes a dioptric imaging opticalsystem; a second imaging optical subsystem with a concave reflectingmirror and a second optical axis, which is arranged in an optical pathbetween the first imaging optical subsystem and the second surface; anda third imaging optical subsystem with a third optical axis, which isarranged in an optical path between the second imaging optical subsystemand the second surface and includes a dioptric imaging optical system,wherein the first optical axis and the third optical axis are located ona common axis, and wherein the catadioptric optical system is atelecentric optical systemon both sides of the first surface and thesecond surface.
 37. The catadioptric optical system of claim 36, furthercomprising: a first reflection surface arranged in an optical pathbetween the first imaging optical subsystem and the second imagingoptical subsystem; and a second reflection surface arranged in anoptical path between the second imaging optical subsystem and the thirdimaging optical subsystem.
 38. The catadioptric optical system of claim37, wherein a first intermediate image is formed in an optical pathbetween the first reflection surface and the second imaging opticalsubsystem by the first imaging optical subsystem, and a secondintermediate image is formed in an optical path between the secondimaging optical subsystem and the second reflection surface by thesecond imaging optical subsystem.
 39. The catadioptric optical system ofclaim 38, wherein the following condition is satisfied:|L 1−L 2|/|L 1|<0.15, where a first distance between the firstintermediate image and the concave reflecting mirror in the secondimaging optical subsystem along the optical axis is defined as L1 , anda second distance between the second intermediate image and the concavereflecting mirror in the second imaging optical subsystem along theoptical axis is defined as L2.
 40. The catadioptric optical system ofclaim 37, wherein an intersection line of an extension plane of thefirst reflection surface and an extension plane of the second reflectionsurface is set up so that the first optical axis of the first imagingoptical subsystem, the second optical axis of the second imaging opticalsubsystem and the third optical axis of the third imaging opticalsubsystem intersect at one point.
 41. The catadioptric optical system ofclaim 36, wherein a magnification factor β2 of the second imagingoptical subsystem satisfies the following condition:0.082<|β2|<1.20.
 42. The catadioptric optical system of claim 41,wherein the following condition is satisfied:0.20<|β|/|β1|<0.50, where a magnification of the catadioptric opticalsystem is defined as β, and a magnification of the first imaging opticalsubsystem is defined as β1.
 43. The catadioptric optical system of claim42, wherein following condition is satisfied:|E−D|/|E|<0.24, where a distance between a surface of the first imagingoptical subsystem on a most image side and an exit pupil position alongthe optical axis is defined as E, and a distance by air conversion fromthe surface of the first imaging optical subsystem on the most imageside to the concave reflecting mirror in the second imaging opticalsubsystem along the optical axis is defined as D.
 44. The catadioptricoptical system of claim 41, wherein the second imaging optical subsystemhas at least two negative lenses.
 45. The catadioptric optical system ofclaim 36, wherein 85% of the number of lenses in all lenses constitutingthe catadioptric optical system are arranged along a single opticalaxis, and wherein the first optical axis and the third optical axis formthe single optical axis.
 46. The catadioptric optical system of claim36, wherein the catadioptric optical system forms the reduced image in aposition deviating from a position of a reference optical axis of thecatadioptric optical system on the second surface.
 47. A projectionexposure apparatus comprising: a projection optical system which isarranged in an optical path between a first surface and a second surfacethat projects and exposes a pattern located on the first surface onto aworkpiece located on the second surface, and the projection opticalsystem that comprises: a first imaging optical subsystem including adioptric imaging optical system; a second imaging optical subsystemincluding a concave reflecting mirror; a third imaging optical subsystemincluding a dioptric imaging optical system; a first folding mirrorarranged in an optical path between the first imaging optical subsystemand the second imaging optical subsystem; and a second folding mirrorarranged in an optical path between the second imaging optical subsystemand the third imaging optical subsystem; wherein the first imagingoptical subsystem forms a first intermediate image of the first surfaceinto the optical path between the first imaging optical subsystem andthe second imaging optical subsystem, the second imaging opticalsubsystem forms a second intermediate image of the first surface intothe optical path between the second imaging optical subsystem, andwherein the projection optical system is a telecentric optical system onboth sides of the first surface and the second surface.
 48. Theprojection exposure apparatus of claim 47, wherein: the projectionexposure apparatus projects the pattern on the mask onto the workpieceand exposes the pattern while the mask and the workpiece are moved inthe same direction.
 49. The projection exposure apparatus of claim 48,wherein: the first folding mirror has a first reflecting surface; thesecond folding mirror has a second reflecting surface; and the firstreflecting surface and the second reflecting surface are positioned sothat they do not overlap spatially.
 50. The projection exposureapparatus of claim 49, wherein: the first and the second reflectingsurfaces are substantially flat surfaces.
 51. The projection exposureapparatus of claim 48, wherein: the projection optical system forms areduced image of the pattern onto the workpiece.
 52. The projectionexposure apparatus of claim 48, wherein: at least one of the firstimaging optical subsystem and the third imaging optical subsystemcontains an aperture stop.
 53. The projection exposure apparatus ofclaim 48, wherein: a plurality of optical members in the first imagingoptical subsystem are arranged along a first optical axis extending in astraight line; the concave reflecting mirror in the second imagingoptical subsystem are arranged along a second optical axis; and aplurality of optical members in the third imaging optical subsystem arearranged along a third optical axis extending in a straight line. 54.The projection exposure apparatus of claim 48, wherein: the firstimaging optical subsystem and the third imaging optical subsystem have acommon optical axis; and the first surface and the second surface areorthogonal in a direction of gravity.
 55. The projection exposureapparatus of claim 48, wherein a magnification β2 of the second imagingoptical subsystem satisfies the following condition:0.82<|β2|<1.20.
 56. The projection exposure apparatus of claim 55,wherein the following condition is satisfied:0.20<|β|/|β1|<0.50 wherein a magnification of the projection opticalsystem is defined as β, and a magnification of the first imaging opticalsubsystem is defined as β1.
 57. The projection exposure apparatus ofclaim 48, wherein the following condition is satisfied:0.20<|β|/|β1|<0.50 wherein a magnification of the projection opticalsystem is defined as β, and a magnification of the first imaging opticalsubsystem is defined as β1.
 58. The projection exposure apparatus ofclaim 48, wherein: the concave reflecting mirror in the second imagingoptical subsystem is arranged in the vicinity of a pupil surface of theprojection optical system.
 59. The projection exposure apparatus ofclaim 48, wherein: the first intermediate image is formed in the opticalpath between the first folding mirror and a concave reflecting mirror inthe second imaging optical subsystem; and the second intermediate imageis formed in the optical path between the concave reflecting mirror inthe second imaging optical subsystem and the second folding mirror. 60.The projection exposure apparatus of claim 59, wherein: the firstintermediate image and the second intermediate image are formed in bothsides of a second optical axis of the second imaging optical subsystem.61. The projection exposure apparatus of claim 48, wherein: a secondoptical axis of the second imaging optical subsystem is orthogonal to afirst optical axis of the first imaging optical subsystem and a thirdoptical axis of the third imaging optical subsystem.
 62. The projectionexposure apparatus of claim 61, wherein: the second optical axis of thesecond imaging optical subsystem extends in a straight line.
 63. Theprojection exposure apparatus of claim 48, wherein: an intersection lineof an extension plane of a reflecting surface of the first optical pathfolding mirror and an extension plane of a reflecting surface of thesecond optical path folding mirror intersects with a first optical axisof the first imaging optical subsystem, a second optical axis of thesecond imaging optical subsystem and a third optical axis of the thirdimaging optical subsystem at one point.
 64. The projection exposureapparatus of claim 48, wherein: the first folding mirror has a backsurface reflecting surface for reflecting a beam from the first imagingoptical subsystem to the second imaging optical subsystem; and thesecond folding mirror has a back surface reflecting surface forreflecting a beam from the second imaging optical subsystem to the thirdimaging optical subsystem.
 65. The projection exposure apparatus ofclaim 48, wherein an image of the first surface is formed in a positiondeviating from a position of a reference optical axis of the projectionoptical system on the second surface.
 66. A manufacturing method ofmicro-devices comprising: preparing a mask with a pattern; preparing aworkpiece; projecting the pattern onto the workpiece using theprojection exposure apparatus of claim
 48. 67. An exposure method forprojecting a pattern onto a workpiece via a projection optical system,the method comprising: directing an illuminating light in theultraviolet region to the pattern; directing the illuminating light to afirst imaging optical subsystem including a dioptric imaging opticalsystem via the pattern to form a first intermediate image of thepattern; directing the illuminating light from the first intermediateimage to a second imaging optical subsystem including a concavereflecting mirror to form a second intermediate image; directing theilluminating a light from the second intermediate image to a thirdimaging optical subsystem including a dioptric imaging optical system;deflecting the illuminating light from the first imaging opticalsubsystem by a first folding mirror arranged in an optical path betweenthe first imaging optical subsystem and the second imaging opticalsubsystem; and deflecting the illuminating light from the second imagingoptical subsystem by a second folding mirror arranged in an optical pathbetween the second imaging optical subsystem and the third imagingoptical subsystem, wherein the projection optical system is atelecentric optical system on the pattern side and the workpiece side.68. The exposure method of claim 67, wherein: the pattern is projectedonto the workpiece and exposed while the workpiece is moved relative tothe projection optical system.
 69. The exposure method of claim 67,wherein the first intermediate image of the pattern is formed in anoptical path between the first folding mirror and the second imagingoptical subsystem by the first imaging optical subsystem, and the secondintermediate image is formed in an optical path between the secondimaging optical subsystem and the second folding mirror by the secondimaging optical subsystem.
 70. The exposure method of claim 69, whereinthe following condition is satisfied:|L 1−L 2|/|L 1|<0.15, where a first distance between the firstintermediate image and the concave reflecting mirror in the secondimaging optical subsystem along the optical axis is defined as L1, and asecond distance between the second intermediate image and the concavereflecting mirror in the second imaging optical subsystem along theoptical axis is defined as L2.
 71. The exposure method of claim 67,wherein an intersection line of an extension plane of the first foldingmirror and an extension plane of the second folding mirror is set up sothat an optical axis of the first imaging optical subsystem, an opticalaxis of the second imaging optical subsystem and an optical axis of thethird imaging optical subsystem intersect at one point.
 72. The exposuremethod of claim 67, wherein a magnification factor β2 of the secondimaging optical subsystem satisfies the following condition:0.082<|β2|<1.20.
 73. The exposure method of claim 72, wherein thefollowing condition is satisfied:0.20<|β|/|β1|<0.50, where a magnification of the catadioptric opticalsystem is defined as β, and a magnification of the first imaging opticalsubsystem is defined as β1.
 74. The exposure method of claim 73, whereinthe following condition is satisfied:|E−D|/|E|<0.24, where a distance between a surface of the first imagingoptical subsystem on a most image side and an exit pupil position alongthe optical axis is defined as E, and a distance by air conversion fromthe surface of the first imaging optical subsystem on the most imageside to the concave reflecting mirror in the second imaging opticalsubsystem along the optical axis is defined as D.
 75. The exposuremethod of claim 72, wherein the second imaging optical subsystem has atleast two negative lenses.
 76. The exposure method of claim 67, wherein85% of the number of lenses in all lenses constituting the catadioptricoptical system are arranged along a single optical axis, and wherein anoptical axis of the first imaging optical subsystem and an optical axisof the third imaging optical subsystem form the single optical axis. 77.The exposure method of claim 67, further comprising: the step of formingan image in a position deviating from a position of a reference opticalaxis of the third imaging optical subsystem on the workpiece.
 78. Amanufacturing method of micro-devices comprising the steps of: preparinga pattern; preparing a workpiece; and exposing the pattern onto theworkpiece with the exposure method of claim
 67. 79. A catadioptricoptical system forming a reduced image of a first surface onto a secondsurface comprising: a first imaging optical subsystem with a firstoptical axis, which is arranged in an optical path between the firstsurface and the second surface and includes a dioptric imaging opticalsystem; a second imaging optical subsystem with a concave reflectingmirror and a second optical axis, which is arranged in an optical pathbetween the first imaging optical subsystem and the second surface; athird imaging optical subsystem with a third optical axis, which isarranged in an optical path between the second imaging optical subsystemand the second surface and includes a dioptric imaging optical system; afirst folding mirror which is arranged in an optical path between thefirst imaging optical subsystem and the second imaging opticalsubsystem; and a second folding mirror which is arranged in an opticalpath between the second imaging optical subsystem and the third imagingoptical subsystem, wherein the first optical axis and the third opticalaxis are located on a common axis, wherein the first folding mirror andthe second folding mirror are formed monolithically, and wherein thecatadioptric optical system is a telecentric optical system on bothsides of the first surface and the second surface.
 80. The catadioptricoptical system of claim 79, wherein: a first intermediate image isformed in an optical path between the first folding mirror and thesecond imaging optical subsystem by the first imaging optical subsystem,and a second intermediate image is formed in an optical path between thesecond imaging optical subsystem and the second folding mirror by thesecond imaging optical subsystem.
 81. The catadioptric optical system ofclaim 80, wherein the following condition is satisfied:|L 1−L 2|/|L 1|<0.15, where a first distance between the firstintermediate image and the concave reflecting mirror in the secondimaging optical subsystem along the optical axis is defined as L1, and asecond distance between the second intermediate image and the concavereflecting mirror in the second imaging optical subsystem along theoptical axis is defined as L2.
 82. The catadioptric optical system ofclaim 79, wherein an intersection line of an extension plane of thefirst folding mirror and an extension plane of the second folding mirroris set up so that the first optical axis of the first imaging opticalsubsystem, the second optical axis of the second imaging opticalsubsystem and the third optical axis of the third imaging opticalsubsystem intersect at one point.
 83. The catadioptric optical system ofclaim 79, wherein a magnification factor β2 of the second imagingoptical subsystem satisfies the following condition:0.082<|β2|<1.20.
 84. The catadioptric optical system of claim 83,wherein the following condition is satisfied:0.20<|β|/|β1|<0.50, where a magnification of the catadioptric opticalsystem is defined as β, and a magnification of the first imaging opticalsubsystem is defined as β1.
 85. The catadioptric optical system of claim84, wherein the following condition is satisfied:|E−D|/|E|<0.24, where a distance between a surface of the first imagingoptical subsystem on a most image side and an exit pupil position alongthe optical axis is defined as E, and a distance by air conversion fromthe surface of the first imaging optical subsystem on the most imageside to the concave reflecting mirror in the second imaging opticalsubsystem along the optical axis is defined as D.
 86. The catadioptricoptical system of claim 83, wherein the second imaging optical subsystemhas at least two negative lenses.
 87. The catadioptric optical system ofclaim 86, wherein the at least two negative lenses have a meniscus lens.88. The catadioptric optical system of claim 79, wherein 85% of thenumber of lenses in all lenses constituting the catadioptric opticalsystem are arranged along a single optical axis, and wherein the firstoptical axis and the third optical axis form the single optical axis.89. The catadioptric optical system of claim 79, wherein thecatadioptric optical system forms the reduced image in a positiondeviating from a position of a reference optical axis of thecatadioptric optical system on the second surface.
 90. A catadioptricoptical system forming an image of a first surface onto a second surfacecomprising: a first imaging optical subsystem with a first optical axis,which is arranged in an optical path between the first surface and thesecond surface and includes a dioptric imaging optical system; a secondimaging optical subsystem with a concave reflecting mirror and a secondoptical axis, which is arranged in an optical path between the firstimaging optical subsystem and the second surface; a third imagingoptical subsystem with a third optical axis, which is arranged in anoptical path between the second imaging optical subsystem and the secondsurface and includes a dioptric imaging optical system; a first foldingmirror which is arranged in an optical path between the first imagingoptical subsystem and the second imaging optical subsystem; and a secondfolding mirror which is arranged in an optical path between the secondimaging optical subsystem and the third imaging optical subsystem,wherein the first optical axis and the third optical axis are located ona common axis, wherein an intersection line of an extension plane of areflecting surface of the first folding mirror and an extension plane ofa reflecting surface of the second folding mirror is on the common axis,and wherein the catadioptric optical system is a telecentric opticalsystem on both sides of the first surface and the second surface. 91.The catadioptric optical system according to claim 90, wherein the firstfolding mirror and the second folding mirror are formed monolithically.92. The catadioptric optical system of claim 91, wherein the first andthe second folding mirrors have substantially flat reflection surfaces.93. The catadioptric optical system of claim 90, wherein at least one ofthe first imaging optical subsystem and the third imaging opticalsubsystem contains an aperture stop.
 94. The catadioptric optical systemof claim 90, wherein a plurality of optical members in the first imagingoptical subsystem are arranged along the first optical axis extending ina straight line, the concave reflecting mirror in the second imagingoptical subsystem is arranged along the second optical axis, and aplurality of optical members in the third imaging optical subsystem arearranged along the third optical axis extending in a straight line. 95.The catadioptric optical system of claim 94, wherein 85% of the numberof lenses in all lenses constituting the catadioptric optical system arearranged along the common axis.
 96. The catadioptric optical system ofclaim 94, wherein the second optical axis of the second imaging opticalsubsystem is orthogonal to the first optical axis of the first imagingoptical subsystem and the third optical axis of the third imagingoptical subsystem.
 97. The catadioptric optical system of claim 90,wherein the first surface and the second surface are orthogonal in adirection of gravity.
 98. The catadioptric optical system of claim 90,wherein a magnification factor β2 of the second imaging opticalsubsystem satisfies the following condition:0.082<|β2|<1.20.
 99. The catadioptric optical system of claim 98,wherein the following condition is satisfied:0.20<|β|/|β1|<0.50, wherein a magnification of the projection opticalsystem is defined as β, and a magnification of the first imaging opticalsubsystem is defined as β1.
 100. The catadioptric optical system ofclaim 98, wherein the second imaging optical subsystem has at least twonegative lenses.
 101. The catadioptric optical system of claim 90,wherein the following condition is satisfied:0.20<|β|/|β1|<0.50, wherein a magnification of the projection opticalsystem is defined as β, and a magnification of the first imaging opticalsubsystem is defined as β1.
 102. The catadioptric optical system ofclaim 90, wherein the concave reflecting mirror in the second imagingoptical subsystem is arranged in the vicinity of a pupil surface of theprojection optical system.
 103. The catadioptric optical system of claim90, wherein a first intermediate image is formed in the optical pathbetween the first folding mirror and the concave reflecting mirror inthe second imaging optical subsystem, and a second intermediate image isformed in the optical path between the concave reflecting mirror in thesecond imaging optical subsystem and the second folding mirror.
 104. Thecatadioptric optical system of claim 103, wherein the first intermediateimage and the second intermediate image are formed in both sides of thesecond optical axis of the second imaging optical subsystem.
 105. Thecatadioptric optical system of claim 103, wherein the followingcondition is satisfied:|L 1−L 2|/|L 1|<0.15, where a first distance between the firstintermediate image and the concave reflecting mirror in the secondimaging optical subsystem along the optical axis is defined as L1, and asecond distance between the second intermediate image and the concavereflecting mirror in the second imaging optical subsystem along theoptical axis is defined as L2.
 106. The catadioptric optical system ofclaim 103, wherein the second optical axis of the second imaging opticalsubsystem extends in a straight line.
 107. The catadioptric opticalsystem of claim 90, wherein the intersection line of the extension planeof the reflecting surface of the first optical path folding mirror andthe extension plane of the reflecting surface of the second optical pathfolding mirror intersects with the first optical axis of the firstimaging optical subsystem, the second optical axis of the second imagingoptical subsystem and the third optical axis of the third imagingoptical subsystem at one point.
 108. The catadioptric optical system ofclaim 90, wherein the image of the first surface is formed in a positiondeviating from a position of a reference optical axis of the projectionoptical system on the second surface.